Aldehydes and Ketones

Question 1

2 general rxns

Answer 1

nucleophilic addition, nucleophilic substitution

Question 2

Difference between addition and substitution

Answer 2

addition = OH and Nu
substitution = Nu

Question 3

Summary

Answer 3

1. Reduction with metal hydrides
2. catalytic hydrogenation
3. oxidation of aldehydes
4. Grignard rxn
5. addition of HCN
6. nucleophilic addition of amines
7. Hydration
8. Wolff-Kishner rxn
9. Nucleophilic addition of OH
10. Wittig rxn
11. Conjugate nucleophilic addition
12. Conjugate addition of amines
13. Conjugate addition of water
14. Conjugate addition of alkyl groups

Question 4

Reduction

Answer 4

rgts: LiAlH4 (anhydrous), or NaBH4, CH3OH and H3O+
products:
aldehyde = primary OH
ketone = secondary OH

Question 5

Catalytic Hydrogenation

Answer 5

rgts: H2 and Pd-C
products:
aldehyde = primary OH
ketone = secondary OH

Question 6

difference between metal hydrides and H2 in Pd-C

Answer 6

Hydrides: reduce C=O
1 H2 in Pd-C: reduce C=C
xs H2 in Pd-C: reduce C=C and C=O

Question 7

Stereochemistry of Carbonyl Reduction

Answer 7

addition of hydride
from the front: (S) OH
from behind: (R) OH

Question 8

Enantioselective Carbonyl Reductions

Answer 8

(S)-CBS: delivers hydride from the front (R product)

(R)-CBS: delivers hydride from the back (S product)

Question 9

Oxidation of CHO

Answer 9

rgts: CrO3, Na2Cr2O7, K2Cr2O7, KMnO4 and H2SO4, H2O
products: COOH + Cr3+

rgts: Ag2O, NH4OH (tollens)
products: COOH + Ag

Question 10

can u oxidize ketone? why?

Answer 10

no, because no H

Question 11

Grignard rnx

Answer 11

rgts: RMgX, ether and H3O+
products:
aldehyde = secondary OH
ketone = tertiary OH

Question 12

difference between hydride reduction and grignard

Answer 12

hydride: adds H and OH
grignard: adds OH and R

Question 13

Addition of HCN

Answer 13

rgts: HCN
products: cyanohydrins

Question 14

Reactions of Cyanohydrins

Answer 14

rgts: LiAlH4, THF and H2O
products: CN becomes amine

rgts: H3O+, heat
products: CN becomes COOH

Question 15

Nucleophilic addition of amines

Answer 15

starting: aldehyde or ketone
rgt and products:
primary amine = imine
secondary amine = enamine

Question 16

Addition or primary amines

Answer 16

rgts: RNH2 and mild acid
products: imine + H2O

Question 17

Addition of secondary amines

Answer 17

rgts: HNR2
products: enamine + H2O

Question 18

Hydrolysis of imine and enamine

Answer 18

forms aldehyde and ketones

Question 19

Hydration of carbonyl compound

Answer 19

rgts: H2O
products: gem-diol or hydrate

Question 20

Gem-diol yields

Answer 20

Electron-donating: decrease
Electron-withdrawing: increase

Question 21

Base-catalyzed vs Acid-Catalyzed H2O addition

Question 22

Wolff-Kishner rxn (Nucleophilic addition of Hydrazine)

Answer 22

rgts: hydrazine (H2NNH2) and KOH
products: alkane + N2 + H2O

Question 23

Nucleophilic additon of OH

Answer 23

rgts: 2 ROH and acid catalyst
products: acetals

Question 24

Wittig reaction

Answer 24

rgts: phosphorus ylide and THF
products: alkene

Question 25

Conjugate nucleophilic addition

Answer 25

direct (1,2) addition and conjugate (1,4) addition

Question 26

Conjugate addition of amines

Answer 26

rgts: RNH2 products: amino ketone

Question 27

Conjugate addition of water

Answer 27

rgts: H2O products: hydroxy aldehyde or ketone

Question 28

Conjugate addition of alkyl groups by diorganocopper rxn

Answer 28

rgts: R2CuLi, ether and H3O+ products: ketone to ketone