Chapter 09 Wade 7th_CGD

7/24/2019 Chapter 09 Wade 7th_CGD

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Chapter 9

2010,

Prentice Hall

Organic Chemistry, 7thEdition

L. G. Wade, Jr.

Alkyne


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Chapter 9 2

!ntrod"ction

# Alkyne contain a triple $ond.

# General %or&"la i CnH2n'2.

# ()o ele&ent o% "nat"ration %or eachtriple $ond.

# *o&e reaction ree&$le the reaction

o% alkene, like addition and o+idation.# *o&e reaction are peci%ic to alkyne.


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Chapter 9

-o&enclat"re !/PAC

# ind the lonet chain containin the

triple $ond.

# Chane -aneendin to -yne.

# -"&$er the chain, tartin at the end

cloet to the triple $ond.

# Gie $ranche or other "$tit"ent a

n"&$er to locate their poition.


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Chapter 9 3

E+a&ple o% -o&enclat"re

# All other %"nctional ro"p, e+cept ether and

halide hae a hiher priority than alkyne.


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Chapter 9 4

Co&&on -a&e

-a&ed a "$tit"ted acetylene.

&ethylacetylene

5ter&inal alkyne6

io$"tyliopropylacetylene

5internal alkyne6

CH CH

CH

CH2 C C CH

CH

CH

CH C CH


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Chapter 9

Phyical Propertie

# -onpolar, inol"$le in )ater.

# *ol"$le in &ot oranic olent.

# 8oilin point are i&ilar to alkane o% a&e

ie.

# Le dene than )ater.

# /p to %o"r car$on, a at roo&

te&perat"re.


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Chapter 9 7

Acetylene

# Acetylene i "ed in )eldin torche.

# !n p"re o+yen, te&perat"re o% %la&e

reache 2:00C.# !t )o"ld iolently deco&poe to it

ele&ent, $"t the cylinder on the torch

contain cr"hed %ire$rick )et )ithacetone to &oderate it.


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Chapter 9 :

*ynthei o% Acetylene

# Heat coke )ith li&e in an electric %"rnace

to %or& calci"& car$ide.

#(hen drip )ater on the calci"& car$ide

coke lime

(hi reaction )a "ed to prod"ce liht %or &iner; la&p and %or the tae.

C Ca


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Chapter 9 9

>olec"lar *tr"ct"re o% Acetylene

# (riple'$onded car$on hae sphy$rid or$ital.# A i&a $ond i %or&ed $et)een the car$on $y

oerlap o% the spor$ital.

# *i&a $ond to the hydroen are %or&ed $y "inthe econd spor$ital.

# *ince the spor$ital are linear, acetylene )ill $e alinear &olec"le.


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Chapter 9 10


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Chapter 9 11

8ond Lenth

# (riple $ond are horter than do"$le or inle$ond $eca"e o% the t)o pi oerlappin or$ital.


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Chapter 9 12

Acidity (a$le


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Chapter 9 1

Acidity o% Alkyne

# (er&inal alkyne, are &ore acidic than other

hydrocar$on d"e to the hiher scharacter o%

the sphy$ridied car$on.# (er&inal alkyne can $e deprotonated

?"antitatiely )ith tron $ae "ch a

odi"& a&ide 5'-H26.

# Hydro+ide and alko+ide $ae are not tron

eno"h to deprotonate the alkyne

?"antitatiely.


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Chapter 9 13

or&ation o% Acetylide !on

# H=can $e re&oed %ro& a ter&inal alkyne $y odi"& a&ide, -a-H2.

# (he acetylide ion i a tron n"cleophile that can eaily do addition and "$tit"tion reaction.


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Chapter 9 14

Acetylide !on in *-2 @eaction

#


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Chapter 9 1

Acetylide !on a *tron 8ae

# Acetylide ion are alo tron $ae. !% the

*-2 reaction i not poi$le, then aneli&ination 5E26 )ill occ"r.


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Chapter 9 17

Show how to synthesize 3-decyne from acetylene and any necessary alkyl halides.

Another name for 3-decyne is ethyl n-hexylacetylene. It can be made by adding an ethyl group and a

hexyl group to acetylene. This can be done in either order; we begin by adding the hexyl group.

*oled Pro$le& 1

*ol"tion


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Chapter 9 1:

Addition to Car$onyl Co&po"nd

# -"cleophile can attack the car$onyl car$on

%or&in an alko+ide ion )hich on protonation)ill %or& an alcohol.


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Chapter 9 19

>echani& o% Acetylenic Alcohol

or&ation


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Chapter 9 20

Add to Aldehyde

Prod"ct i a econdary alcohol, one @

ro"p %ro& the acetylide ion, the other

@ ro"p %ro& the aldehyde.

+ C O

CH3

H

CH3 C C CH3 C C C

CH3

H

O

+H2O O

H

HH

CH3 C C C O H

CH3

H


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Chapter 9 21

Add to Detone

Prod"ct i a tertiary alcohol.

+ C O

CH3

CH3

CH3 C C CH3 C C C

CH3

CH3

O

+H2O O

H

HH

CH3 C C C O H

CH3

CH3


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Chapter 9 22

Show how you would synthesize the following compound, beginning with acetylene and any necessary

additional reagents.

We need to add two groups to acetylene: an ethyl group and a six carbon aldehyde (to form the

secondary alcohol). If we formed the alcohol group first, the weakly acidic OH group would

interfere with the alkylation by the ethyl group. Therefore, we should add the less reactive ethyl group

first, and add the alcohol group later in the synthesis.

The ethyl group is not acidic, and it does not interfere with the addition of the second group:

*oled Pro$le& 2

*ol"tion


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Chapter 9 2

ehydrohaloenation @eaction

# @e&oal o% t)o &olec"le o% H %ro& aicinal or e&inal dihalide prod"ce an

alkyne.# irt tep 5'H6 i eay, %or& inyl

halide.

# *econd tep, re&oal o% H %ro& theinyl halide re?"ire ery tron $aeand hih te&perat"re.


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Chapter 9 23

@eaent %or Eli&ination

# >olten D


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Chapter 9 24

(riple'8ond >iration

/nder e+tre&ely $aic condition, an acetylenic triple $ond can

&irate alon the car$on chain $y repeated deprotonation and

reprotonation.


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Chapter 9 2

Addition @eaction

# *i&ilar to addition to alkene.

# Pi $ond $eco&e t)o i&a $ond.

# /"ally e+other&ic.#


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Chapter 9 27

Catalytic Hydroenation o%

Alkyne

# ()o &olec"le o% hydroen can add acro the triple$ond to %or& the correpondin alkane.

# A catalyt "ch a Pd, Pt, or -i need to $e "ed %orthe reaction to occ"r.

# /nder thee condition the alkyne )ill $e co&pletelyred"cedF the alkene inter&ediate cannot $e iolated.


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Chapter 9 2:

Hydroenation )ith Lindlar;

Catalyt

# (he catalyt "ed %or the hydroenation reaction i partiallydeactiated 5poioned6, the reaction can $e topped a%ter theaddition o% only one &ole o% hydroen.

# (he catalyt "ed i co&&only kno)n a Lindlar catalyt andit i co&poed o% po)dered $ari"& "l%ate, coated )ithpalladi"& poioned )ith ?"inoline.

# (he reaction prod"ce alkene )ith ci tereoche&itry.


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Chapter 9 29

>echani&

# 8oth "$trate, the hydroen and the alkyne, hae to$e ador$ed on the catalyt %or the reaction to occ"r.

#


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Chapter 9 0

@ed"ction o% Alkyne )ith >etal

A&&onia

# (o %or& a tran alkene, t)o hydroen &"t

$e added to the alkyne anti tereoche&itry,o thi red"ction i "ed to conert alkyne to

tran alkene.


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Chapter 9 1

@ed"ction o% Alkyne )ith >etal

A&&onia

# /e dry ice to keep a&&onia li?"id.

# A odi"& &etal diole in the

a&&onia, it loe an electron.

# (he electron i olated $y the

a&&onia, creatin a deep $l"e ol"tion.

NH3 + Na + Na+

NH3 e-


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Chapter 9 2

>echani& o% >etal @ed"ctionStep 1:An electron adds to the alkyne, forming a radical anion.

Step 2:The radical anion is protonated to give a radical.

Step 3:An electron adds to the alkyne, forming an anion.

Step 4:Protonation of the anion gives an alkene.


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Chapter 9

Addition o% Haloen

# Cl2and 8r2add to alkyne to %or& inyl dihalide.

# >ay add yn or anti, o prod"ct i &i+t"re o% cisandtransio&er.

# i%%ic"lt to top the reaction at dihalide.

CHC CH CHC CH

8 r

8 r

CHC CCH

8 r

8 r 8 r

8 r

8 r2

CH2Cl2

8 r2

CH2Cl2


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Chapter 9 3

Addition o% H

#


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Chapter 9 4

>echani& o% Hydroen Halide

Addition

# (he triple $ond a$tract a proton %ro& the hydroenhalide %or&in a inyl cation.

# (he proton add to the leat "$tit"ted car$on.

# (he econd tep o% the &echani& i the attack $ythe halide.


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Chapter 9

Anti'>arkoniko Addition o%

Hydroen 8ro&ide to Alkyne

# 8y "in pero+ide, hydroen $ro&ide can $e added

to a ter&inal alkyne anti'>arkoniko.# (he $ro&ide )ill attach to the leat "$tit"ted

car$on iin a &i+t"re o% ci and tran io&er.


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Chapter 9 7

Hydration o% Alkyne

# >erc"ric "l%ate in a?"eo" "l%"ricacid add Harkoniko orientation, %or&in a inylalcohol 5enol6 that rearrane to aketone.

# Hydro$orationIo+idation add H


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Chapter 9 :

>erc"ric !on Catalyed Hydration

o% Alkyne

# Water can $e added acro the triple $ond in a reactionanaloo" to the o+y&erc"rationIde&erc"ration o% alkene.

# (he hydration i catalyed $y the &erc"ric ion.# !n a typical reaction, a &i+t"re o% &erc"ric acetate in

a?"eo" "l%"ric acid i "ed.# (he addition prod"ce an inter&ediate inyl alcohol 5enol6

that ?"ickly ta"to&erie to the &ore ta$le ketone oraldehyde.


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Chapter 9 9

>echani& o% >erc"ric !on

Catalyed Hydration

# (he electrophilic addition o% &erc"ric in 5H=26 create a inylcar$ocation.

# Water attack the car$ocation and a%ter deprotonation, %or&an orano&erc"rial alcohol.

# Hydrolyi o% the alcohol re&oe the &erc"ry, %or&in ainyl alcohol co&&only re%erred to a enol.


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Chapter 9 30

DetoIEnol (a"to&eri&

# Enol are not ta$le and they io&erie to the

correpondin aldehyde or ketone in a

proce kno)n a keto'enol ta"to&eri&.


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Chapter 9 31

Hydro$orationI


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Chapter 9 32


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Chapter 9 3


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Chapter 9 33

Per&ananate


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Chapter 9 34

Per&ananate


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Chapter 9 3

Chapter 09 Wade 7th_CGD

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