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©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Chapter 12Aldehydes and Ketones
CHEM 240: Fall 2016
Prof. Greg Cook
cook.chem.ndsu.nodak.edu/chem240
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Carbonyl Compounds
2
R H
O
R R'
O
ketonealdehyde
R OR'
O
ester
R OH
O
carboxylic acid
R X
O
acid halide
R SR'
O
thioester
R NH2
O
amide
R X
O
acid anhydride
R
O
HO OH
O
carbonic acid
H2N NH2
O
urea
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Naming aldehydes and ketones
3
H H
O
methanalformaldehyde
H3C H
O
ethanalacetaldehyde
H
O
benzaldehydebenzene carbaldehyde
2,4-pentanedioneacetylacetone
OO
H
O
propenalacrolein
H3C CH3
O
propanoneacetone
O
trans-hex-4-en-2-one
CH3
O
acetophenone
O
benzophenone
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Carbonyl Substituents
4
R
O
acyl group
H
O
formylH3C
O
acetyl
O
benzoyl
methyl 3-oxopentanoateOCH3
OO
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Nature of the C=O bond
5
O
©2016 Gregory R Cook
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Types of Nucleophiles
6
©2016 Gregory R Cook
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Addition of Grignard Reagents
7©2016 Gregory R Cook
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Addition of Grignard Reagents
8
©2016 Gregory R Cook
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Types of Nucleophiles
9©2016 Gregory R Cook
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Mechanism of hydration
10
O
acetone acetonehydrate
HO OH+ H2O H H
O
formaldehydeH Hformaldehydehydrate
HO OH+ H2O
99.9%99.9%
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
General Activation - acid vs base
11
O
Acid Catalyzed Hydration
HA OH
moreelectrophilic
H2OHO O
HH
A HO OH
acid activates the carbonyl making it more reactive (more electrophilic) so water can add
O H+ O H
carbonyl is more electrophilic
O H -OH
nucleophile is more reactive
Nuc H Nuc
Base Catalyzed Hydration
O OH O OH HO OH
hydroxide is a more reactive nucleophile than water and can add more readily to the carbonyl
H2O
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Addition of Alcohols
12
O
a hemiacetal
+ ROH2H+
HO OR
an acetal
RO OR
(+ ROH) (+ ROH)(- H2O)
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Addition of Alcohols
12
O
a hemiacetal
+ ROH2H+
HO OR
an acetal
RO OR
(+ ROH) (+ ROH)(- H2O)
O
HA
OH
OHR
O O HR
H A O O R
H
Hemiacetal
-H2O
O RO R
resonance structures
HA
O O R
H
R
A
O O RR
OH
resonance structures
HO R
O O R
H
H
©2016 Gregory R Cook
cook.chem.ndsu.nodak.edu/chem240
Acetals are important in sugars
13
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Acetals are carbonyl protecting groups
14©2016 Gregory R Cook
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Formation of Imines
15
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Imines have important biological function
16©2016 Gregory R Cook
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Reduction of imines
17
©2016 Gregory R Cook
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Keto-Enol Tautomerism
18©2016 Gregory R Cook
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Racemization
19
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Enols are nucleophilic
20©2016 Gregory R Cook
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Oxidation of Aldehydes
21
©2016 Gregory R Cook
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Oxidation of Aldehydes
21©2016 Gregory R Cook
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Reduction of Aldehydes and Ketones
22
a carbonyl compound
C
OH
" "
an alcohol
CHO H
NaBH4
LiAlH4
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