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©2016 Gregory R Cook cook.chem.ndsu.nodak.edu/chem240 Chapter 12 Aldehydes 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 ketone aldehyde R OR' O ester R OH O carboxylic acid R X O acid halide R SR' O thioester R NH 2 O amide R X O acid anhydride R O HO OH O carbonic acid H 2 N NH 2 O urea ©2016 Gregory R Cook cook.chem.ndsu.nodak.edu/chem240 Naming aldehydes and ketones 3 H H O methanal formaldehyde H 3 C H O ethanal acetaldehyde H O benzaldehyde benzene carbaldehyde 2,4-pentanedione acetylacetone O O H O propenal acrolein H 3 C CH 3 O propanone acetone O trans-hex-4-en-2-one CH 3 O acetophenone O benzophenone ©2016 Gregory R Cook cook.chem.ndsu.nodak.edu/chem240 Carbonyl Substituents 4 R O acyl group H O formyl H 3 C O acetyl O benzoyl methyl 3-oxopentanoate OCH 3 O O ©2016 Gregory R Cook cook.chem.ndsu.nodak.edu/chem240 Nature of the C=O bond 5 O ©2016 Gregory R Cook cook.chem.ndsu.nodak.edu/chem240 Types of Nucleophiles 6
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Chapter 12 O Aldehydes and Ketones - The Cook …cook.chem.ndsu.nodak.edu/.../08/240-16-Chapter12-6pg.pdf©2016 Gregory R Cook 240 Chapter 12 Aldehydes and Ketones CHEM 240: Fall 2016

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Page 1: Chapter 12 O Aldehydes and Ketones - The Cook …cook.chem.ndsu.nodak.edu/.../08/240-16-Chapter12-6pg.pdf©2016 Gregory R Cook 240 Chapter 12 Aldehydes and Ketones CHEM 240: Fall 2016

©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

cook.chem.ndsu.nodak.edu/chem240

Types of Nucleophiles

6

Page 2: Chapter 12 O Aldehydes and Ketones - The Cook …cook.chem.ndsu.nodak.edu/.../08/240-16-Chapter12-6pg.pdf©2016 Gregory R Cook 240 Chapter 12 Aldehydes and Ketones CHEM 240: Fall 2016

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Addition of Grignard Reagents

7©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Addition of Grignard Reagents

8

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Types of Nucleophiles

9©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

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)

Page 3: Chapter 12 O Aldehydes and Ketones - The Cook …cook.chem.ndsu.nodak.edu/.../08/240-16-Chapter12-6pg.pdf©2016 Gregory R Cook 240 Chapter 12 Aldehydes and Ketones CHEM 240: Fall 2016

©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

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Acetals are carbonyl protecting groups

14©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Formation of Imines

15

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Imines have important biological function

16©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Reduction of imines

17

Page 4: Chapter 12 O Aldehydes and Ketones - The Cook …cook.chem.ndsu.nodak.edu/.../08/240-16-Chapter12-6pg.pdf©2016 Gregory R Cook 240 Chapter 12 Aldehydes and Ketones CHEM 240: Fall 2016

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Keto-Enol Tautomerism

18©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Racemization

19

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Enols are nucleophilic

20©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Oxidation of Aldehydes

21

©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Oxidation of Aldehydes

21©2016 Gregory R Cook

cook.chem.ndsu.nodak.edu/chem240

Reduction of Aldehydes and Ketones

22

a carbonyl compound

C

OH

" "

an alcohol

CHO H

NaBH4

LiAlH4