7212019 Wade PowerpointLecture for Chapter 3
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Chapter 3
Structure andStereochemistry
of Alkanes
Organic Chemistry 8th Edition
L G Wade Jr
7212019 Wade PowerpointLecture for Chapter 3
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Hydrocarbon
Classification Review
7212019 Wade PowerpointLecture for Chapter 3
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Alkaneshellipbull Have all C-C single bonds
bull Are said to be saturated with hydrogens
bull Have a CH Ratio of C nH n
bullHave same ratio for branched alkanes
bull Have homologs CH 3CH $nCH 3
C
H
C
H
H
H C H
H
H
C H
H
H
Isobutane C4H10
C
H
C
H
H
H C C
H
HH H
H
H
Butane C4H10
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 476
rob 3-amp (sing the general
formula for alkaneshellip
a$ predict the molecular formula of the
C ) straight chain alkane
b$ redict the molecular formula of
+-diethyl-amp-3+)-dimethyloctyl$
triacontane
+ an alkane containing
carbon atoms
7212019 Wade PowerpointLecture for Chapter 3
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Alkane ames
bull All end in ane bull methane+ ethane+ propane and butane
are historical names
bull pentane+ he0ane+ heptane+ octane+nonane and decane are from the 1reek
bull 2ou must know how to count to ten
in rganic Chemistry4
7212019 Wade PowerpointLecture for Chapter 3
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Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
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ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
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7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
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oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
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Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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Hydrocarbon
Classification Review
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 376
Alkaneshellipbull Have all C-C single bonds
bull Are said to be saturated with hydrogens
bull Have a CH Ratio of C nH n
bullHave same ratio for branched alkanes
bull Have homologs CH 3CH $nCH 3
C
H
C
H
H
H C H
H
H
C H
H
H
Isobutane C4H10
C
H
C
H
H
H C C
H
HH H
H
H
Butane C4H10
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 476
rob 3-amp (sing the general
formula for alkaneshellip
a$ predict the molecular formula of the
C ) straight chain alkane
b$ redict the molecular formula of
+-diethyl-amp-3+)-dimethyloctyl$
triacontane
+ an alkane containing
carbon atoms
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 576
Alkane ames
bull All end in ane bull methane+ ethane+ propane and butane
are historical names
bull pentane+ he0ane+ heptane+ octane+nonane and decane are from the 1reek
bull 2ou must know how to count to ten
in rganic Chemistry4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 676
Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
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ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
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7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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Alkaneshellipbull Have all C-C single bonds
bull Are said to be saturated with hydrogens
bull Have a CH Ratio of C nH n
bullHave same ratio for branched alkanes
bull Have homologs CH 3CH $nCH 3
C
H
C
H
H
H C H
H
H
C H
H
H
Isobutane C4H10
C
H
C
H
H
H C C
H
HH H
H
H
Butane C4H10
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 476
rob 3-amp (sing the general
formula for alkaneshellip
a$ predict the molecular formula of the
C ) straight chain alkane
b$ redict the molecular formula of
+-diethyl-amp-3+)-dimethyloctyl$
triacontane
+ an alkane containing
carbon atoms
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 576
Alkane ames
bull All end in ane bull methane+ ethane+ propane and butane
are historical names
bull pentane+ he0ane+ heptane+ octane+nonane and decane are from the 1reek
bull 2ou must know how to count to ten
in rganic Chemistry4
7212019 Wade PowerpointLecture for Chapter 3
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Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
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aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
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oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
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Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
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EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
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Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
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=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
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Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 476
rob 3-amp (sing the general
formula for alkaneshellip
a$ predict the molecular formula of the
C ) straight chain alkane
b$ redict the molecular formula of
+-diethyl-amp-3+)-dimethyloctyl$
triacontane
+ an alkane containing
carbon atoms
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 576
Alkane ames
bull All end in ane bull methane+ ethane+ propane and butane
are historical names
bull pentane+ he0ane+ heptane+ octane+nonane and decane are from the 1reek
bull 2ou must know how to count to ten
in rganic Chemistry4
7212019 Wade PowerpointLecture for Chapter 3
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Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
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oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
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Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
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EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
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Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
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=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
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Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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Alkane ames
bull All end in ane bull methane+ ethane+ propane and butane
are historical names
bull pentane+ he0ane+ heptane+ octane+nonane and decane are from the 1reek
bull 2ou must know how to count to ten
in rganic Chemistry4
7212019 Wade PowerpointLecture for Chapter 3
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Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
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Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
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Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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Counting to 5en in
rganic Chemistry Number of Carbons Alkane Name Formula
1 methane CH4
2 ethane CH3CH3
3 propane CH3CH2CH3
4 butane CH3(CH2)2CH3
5 pentane CH3(CH2)3CH3
6 hexane CH3(CH2)4CH3
7 heptane CH3(CH2)5CH3
otane CH3(CH2)6CH3
nonane CH3(CH2)7CH3
1 $eane CH3(CH2)CH3
7212019 Wade PowerpointLecture for Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
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Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
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ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
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7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
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Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
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=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
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Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
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Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
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Chair Conformer of
Cyclohe0ane
oat Conformer of
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
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A0ial and =uatorial
ositions
Eonosubstituted
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
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rob 3-3K ame the
following compounds
a b c
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=nd of Chapter 3
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5here are two
nomenclature systems
in organic chemistry
6 Common ames 7 from historical
usage8 used for namingsimpler9smaller compounds only
66 6(AC ames 7 a systematic
naming system that follows
specific rules8 must use when
naming more comple0 molecules
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
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Alkane =0amples
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
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ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
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7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
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aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
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oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
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Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
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EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
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Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
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=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
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Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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Common ame refi0es
bull 6sobutane+ isomer of butane bull 6sopentane+ isohe0ane+ etc+ methyl
branch on ne0t-to-last carbon in chain
bull eopentane+ most highly branched bull ive possible isomers of he0ane+
amp isomers of octane+ and lt) for
decane4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 976
Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
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6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1676
aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 976
Alkane =0amples
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1076
6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1676
aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1076
6(AC aming rocedure
amp ind the longest continuous carbonchain
umber the carbons+ starting closest tothe first branch
3 ame the groups attached to the chain+using the carbon number as the locator
Alphabetigte substituents
) (se di-+ tri-+ tetra-+ etc+ for multiples ofthe same substituent
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1176
ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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ongest Chain
bull 5he number of carbons in the longestchain determines the base name+ egethane+ he0ane isted in 5able 3$
bull 6f there are two possible chains with thesame number of carbons+ use the chainwith the most substituents
C
CH3
CH2
CH3
CH CH2 CH2 CH3
CH CH2
CH3
H3C
H3C
3+3+)-trimethyl--propylheptane
7212019 Wade PowerpointLecture for Chapter 3
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7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1276
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1676
aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1376
umber the Carbons
bull Start at the end closest to thefirst attached group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1676
aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1476
umber the Carbons
bull hen multiple substituents are present+ number the parent chain to
give the first substituent the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1576
umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1676
aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
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Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
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Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
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ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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umber the Carbons
bull 6f there is a tie+ then number the parent chain so that the second
substituent gets the lowest
number possible
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
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oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
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ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
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Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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aming Alkyl 1roups
bull CH 3 -+ methyl
bull CH 3 CH -+ ethyl
bull CH 3 CH CH -+ n-propyl bull CH 3 CH CH CH -+ n-butyl
CH3 CH CH2 CH3
sec- butyl
CH3 CH
CH3
CH2
isobutyl
CH3 CH CH3
isopropylCH3C
CH3
CH3tert -butyl
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1776
aming ropyl 1roups
C
H
H
H
C
H
H
C
H
H
H
n-propyl
C
H
H
H
C
H
C
H
H
H
isopropyl
H
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1876
aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
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Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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aming utyl 1roups
C
H
H
H
C
H
C
H
H
C
H
H
H
C
H
H
H
C
H
C
H
HH
C
H
H
n-butyl sec-butyl
A primary carbon A secondary carbon
ampdeg deg
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 1976
aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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aming ranched
utyl 1roups
CHH
H
C
C
H H
C
H
H
H H
CHH
H
C
C
H H
C H
H
H
H
A primary carbon A tertiary carbon
isobutyl tert -butyl
ampdeg 3deg
7212019 Wade PowerpointLecture for Chapter 3
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ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2076
ame the substituents in thefollowing molecules
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2176
ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
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ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
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utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
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ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
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aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
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aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull Alphabetigte substituents by name
bull 6gnore di-+ tri-+ etc for alphabetigting
CHH3C
CH3
CH
CH2CH3
CH2 CH2 CH
CH3
CH3
3-ethyl-+-dimethylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2276
ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
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hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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ist Substituents in
Alphabetical rder bull 6gnore hyphenatied prefi0es like sec- and tert- when alphabetigtingbull ut the prefi0 iso in isopropyl and isobutyl is not hypenated+ so
those groups should be alphabetigted under i
CH3 CH3
CH3
CH3CH3
CH3
3-isopropyl-+-dimethylnonane
7212019 Wade PowerpointLecture for Chapter 3
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hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
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rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
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bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2376
hen there is a tie
between groupshellip6s it )-chloro-amp-bromo+ or amp-chloro-)-bromoB
Always give the lowest number to the
first alphabetical substituent 7 but
2 6 5H= CAS= A 56=4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2476
or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
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Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
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Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
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Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
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Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
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A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
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Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
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amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
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Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
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rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
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=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
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or Cycloalkaneshellip
bull 5he same rules apply want the
lowest combination of numbers
7212019 Wade PowerpointLecture for Chapter 3
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Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
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5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
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Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
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Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
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oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2576
Comple0 Substituents
bull 6f a branch has a branch+ number thecarbons from the point of attachment
bull ame the branch off the branch using
a locator numberbull arentheses are used around the
comple0 branch name
12
3amp-methyl-3-amp+-dimethylpropyl$cyclohe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2676
rob 3- ame the
following alkanes haloalkanes
CH3CH3
CH3
CH3CH3
CH3
Br
CH3 CH3
CH3
CH3
CH3
a b d
3-methylpentane-bromo-3-methylpentane -isopropyl--methyldecane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2776
rob 3-3 rite the
structures for the
following compounds
c -t-butyl--methylheptane d )-isopropyl-3+3+-trimethyloctane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2876
rob 3- rovide the
6(AC name for thesecompounds
CH3 CH3
CH3CH3
CH3 CH3CH3e ook for the most number
of substituents4
3-ethyl-+++)-tetramethylhe0ane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 2976
rob 3- Draw the
structure of the following
b )-amp++-trimethylpropyl$nonane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3076
bull or molecules that are large and comple0+ there are
EA2 more rules to follow using the 6(AC system
bull ften trade names are used for the sake of simplicity bull 5he molecule above is also known as esomepragtole
or e0ium+ which is a drug for acid reflu0
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3176
hysical roperties of
Alkanesbull Solubility hydrophobic 7 water hating
bull Density less than amp g9m float on water+ eg
an oil slick
bull oiling points increase with increasing numberof carbons with branched chains lower than
straight chains$
Eelting points increase with
increasing number of carbons with
branched chains higher than straight$
bull
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3276
oiling oints of Alkanesranched alkanes have less surface area contact+
so weaker intermolecular ondon dispersion$ forces
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3376
Eelting oints of Alkanesbull 6ncreases with increasing number of carbons+ but
the increase is not smoothbull ranched alkanes pack more efficiently into a
crystalline structure+ so have higher mpFs
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3476
ranched Alkanesbull ower bp with increased branching 7 smaller Ds
bull Higher mp with increased branching 7 higher lattice
energy in the solid phase
bull =0amples
H
CH3
CHCH3
CH2 CH2 CH3
bp 60degCmp -154degC
CH3
CHCH3
CH
CH3
CH3
bp 58degC
mp -135degC
bp 50degCmp -8degC
CH3 C
C 3
CH3
CH2 CH3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3576
EaGor (ses of Alkanes
bull C amp-C gases natural gas$bull C 3-C liuified petroleum 1$
bull C ) -C gasoline
bull C I-C amp diesel+ kerosene+ Get fuel bull C amplt -up lubricating oils+ heating oil
bull Source oil44 petroleum refining$il is also the feedstock of almost all organic
chemicals+ eg plastics+ fibers+ and pharmaceuticals4
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3676
Reactions of Alkanes
6 Combustion
CH3CH2CH2CH3 + O2 CO2 + H2Oheat
8 10132
long-chain alkanescatalyst
shorter-chain alkane
CH4 + Cl2 CH3Cl + CH2Cl2 CHCl3 CCl4+ +
heat or light
66 Cracking and hydrocracking
(industrial)
666 Halogenation coming up in CH $
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3776
Conformers of Alkanes
bull Conformers are structures resulting fromfree rotation around C-C single bonds
bull Eay differ in energy 5he lowest-energy
conformer is most prevalentbull Eolecules constantly rotate through all
the possible conformations
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3876
=thane Conformers
bull Staggered conformer has lowest
energy
bull Dihedral angle J KL
H
H
H H
H H
Newman
roetion sawhorse
model
KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 3976
Chater 3
=thane Conformers $bull =clipsed conformer has highest energy
bull Dihedral angle J KL
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4076
Conformational Analysis
bull5orsional strain resistance to rotationbull or ethane+ only amp kM9mol
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4176
5orsional Strain
bull ith a difference of amp kM9mol instability+ at room temperature+ IIN of
the molecules will be in the staggered
conformation
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4276
Chater 3
ropane Conformers
ote slight increase in torsional strain
due to the more bulky methyl group
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4376
utane Conformers C-C3
bull Highest energy has methyl groups totallyeclipsed
bull Eethyl groups e0hibit steric hindrance
bull Dihedral angle J0983088
totally eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4476
ne of the Eost 6mportant Concepts in -Chem
Steric Hindranceinterference between two bulky groups
that are so close together their electron
clouds e0perience a repulsion
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4576
utane Conformers $
bull owest energy has methyl groups anti bull Dihedral angle J amp 0983088
bull Einimal steric hindrance
anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4676
utane Conformers 3$bull Eethyl groups are eclipsed with hydrogens
bull Higher energy than staggered conformerbull Dihedral angle J amp 0983088
bull 6ntermediate steric hindrance
eclipsed
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4776
utane Conformers $
bull 1auche is a staggered conformerbull Eethyls closer than in anti conformer
bull Dihedral angle between methyls J 0983088
gauche
f
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4876
ames of the our
utane Conformers
totally eclipsed gauche eclipsed anti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 4976
Conformational Analysis
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5076
Higher Alkanes
bull Anti conformation is lowest in energybull Straight chain actually is gtiggtag
CH3CH2CH2CH2CH3
CH C
CC
C
H H H H
H H
H H
HH H
C l lk
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5176
Cycloalkanesbull Rings of carbon atoms -CH - groups$
bull ormula C nH n
bull onpolar+ insoluble in water
bull Compact shape
bull Eelting and boiling points similar to branched
alkanes with same number of carbons
bull hat is the smallest cycloalkaneB
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5276
aming Cycloalkanes
bull Cycloalkane usually base compound bull umber carbons in ring if Oamp substituent
bull ant substituents to have lowest possiblenumbers
bull ame as cycloalkyl attachments to chain
CH2CH3
CH2CH3
CH3
amp+amp-diethyl-3-methylcyclopentane -cyclopentylheptane
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5376
rob 3amp14 e +AC
names for the follo-n
a b
CH3CH3
CH3
CH3
CH3
CH3
3ampsec ampbutlamp101amp$methllopentane
3amploproplamp101amp$methllohexane
Ci 5 6 i i
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5476
Cis-5rans 6somerism in
Cycloalkanes
bull Cis like groups on same side of ring
bull 5rans like groups on opposite sides of ring
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5576
bull Carbon atoms in alkanes are sp3 hybridigted
bull 6f cycloalkanes were flat+ what bond angleswould be e0pectedB
bull 5o optimigte the bond angles+ mostcycloalkanes are 5 flat in their moststable conformation
Ring Strain and
Cycloalkane Stability
Ring Strain and
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5676
Ring Strain and
Cycloalkane Stability bull )- and -membered rings are the most stable
because the C-C-C bond angles are closest to ampKI)L
bull )- and -membered rings are favored in organic
chemistry4
bull Angle aeyer$ strain
bull Eeasured by heats of combustion
per -CH -
Heats of Combustion9CH
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5776
Heats of Combustion9CH
Alkane rarr C H
on-cain
658$6 amp 658$6
6$1 686$1664$0 663$6 amp(mol662$4
C l
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5876
Cyclopropanebull arge ring strain due to angle compression
bull Pery reactive+ because of weak bonds
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 5976
Cyclopropane $
5orsional strain because ofeclipsed hydrogens
C l b
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6076
Cyclobutane
bull Angle strain due to compressionbull 5orsional strain partially relieved by
ring-puckering
C l t
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6176
Chater 3
Cyclopentanebull 6f planar+ angles would be ampK L + but all
hydrogens would be eclipsed
bull uckered conformer reduces torsional
strain
C l h
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6276
Cyclohe0anebull
Combustion data shows itFs unstrainedbull Angles would be ampK L + if planar
bull 5he chair conformer has ampKI) L bondangles and all hydrogens are staggered
bull o angle strain and no torsional strain
Chair Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6376
Chair Conformer of
Cyclohe0ane
oat Conformer of
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6476
oat Conformer of
Cyclohe0ane
Conformational =nergy
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6576
Conformational =nergy
Diagram
A0ial and =uatorial
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6676
A0ial and =uatorial
ositions
Eonosubstituted
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6776
Eonosubstituted
Cyclohe0aneshich conformer has minimal steric hindranceB
amp 3 Di i l 6 t ti
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6876
amp+3-Dia0ial 6nteractions
minimal steric hindrance
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 6976
Disubstituted Cyclohe0anes
Cis-amp+3-dia0ial conformer has serious steric
hindrance4
C
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7076
Cis-5rans 6somers
onds that are cis+ alternate a0ial- euatorial around the ring
CH3
CH3
ne a0ial+ one euatorial
ulky 1roups
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7176
ulky 1roupsbull 1roups like t-butyl cause a large energy
difference between the a0ial and euatorial
conformer
bull Eost stable conformer puts t-butyl
euatorial regardless of other substituents
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7276
rob 3- ame the
following compounds
CH3
H
H
CH3
CH3
CH3
H
H
H
H
CH3
CH3
a b
icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7376
icyclic Alkanes
bull used rings share two adGacent carbons
bull ridged rings share two nonadGacent
carbons bridgehead
carbons
aming icyclic Alkanes
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7476
aming icyclic Alkanes
bull irst name is the prefi0 bicyclo
bull e0t+ put numbers in suare brackets+ in
decreasing numerical order+ of Q of carbons
connected to the bridgehead carbons
bull ast name is the alkane name based onthe total number of carbons in all the rings
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7576
rob 3-3K ame the
following compounds
a b c
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
7212019 Wade PowerpointLecture for Chapter 3
httpslidepdfcomreaderfullwade-powerpointlecture-for-chapter-3 7676
=nd of Chapter 3
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