Aldehydes and Ketones Flashcards
2 general rxns
nucleophilic addition, nucleophilic substitution
Difference between addition and substitution
addition = OH and Nu
substitution = Nu
Summary
- Reduction with metal hydrides
- catalytic hydrogenation
- oxidation of aldehydes
- Grignard rxn
- addition of HCN
- nucleophilic addition of amines
- Hydration
- Wolff-Kishner rxn
- Nucleophilic addition of OH
- Wittig rxn
- Conjugate nucleophilic addition
- Conjugate addition of amines
- Conjugate addition of water
- Conjugate addition of alkyl groups
Reduction
rgts: LiAlH4 (anhydrous), or NaBH4, CH3OH and H3O+
products:
aldehyde = primary OH
ketone = secondary OH
Catalytic Hydrogenation
rgts: H2 and Pd-C
products:
aldehyde = primary OH
ketone = secondary OH
difference between metal hydrides and H2 in Pd-C
Hydrides: reduce C=O
1 H2 in Pd-C: reduce C=C
xs H2 in Pd-C: reduce C=C and C=O
Stereochemistry of Carbonyl Reduction
addition of hydride
from the front: (S) OH
from behind: (R) OH
Enantioselective Carbonyl Reductions
(S)-CBS: delivers hydride from the front (R product)
(R)-CBS: delivers hydride from the back (S product)
Oxidation of CHO
rgts: CrO3, Na2Cr2O7, K2Cr2O7, KMnO4 and H2SO4, H2O
products: COOH + Cr3+
rgts: Ag2O, NH4OH (tollens)
products: COOH + Ag
can u oxidize ketone? why?
no, because no H
Grignard rnx
rgts: RMgX, ether and H3O+
products:
aldehyde = secondary OH
ketone = tertiary OH
difference between hydride reduction and grignard
hydride: adds H and OH
grignard: adds OH and R
Addition of HCN
rgts: HCN
products: cyanohydrins
Reactions of Cyanohydrins
rgts: LiAlH4, THF and H2O
products: CN becomes amine
rgts: H3O+, heat
products: CN becomes COOH
Nucleophilic addition of amines
starting: aldehyde or ketone
rgt and products:
primary amine = imine
secondary amine = enamine
