Aldehydes and Ketones Flashcards
What is the reagent for reduction of aldehydes and ketones?
NaBH4
What is the mechanism for reduction of aldehydes and ketones?
nucleophilic addition
What is the nucleophile for reduction of aldehydes and ketones?
:H-
What is the conditions for reduction of aldehydes and ketones?
acidic solvent
Describe mechanism for reduction of aldehydes and ketones?
(propanal)
1) C is partially positive and O is partially negative. Pair of electrons move from C double bond O to O
2) Lone pair from :H- moves onto partially positive C
3) Lone pair on O attracts H+
What is the reagent for addition of aldehydes and ketones?
KCN
What is the mechanism for addition of aldehydes and ketones?
nucleophilic addition
What is the nucleophile for addition of aldehydes and ketones?
-:C (triple bond) N
What is the condition for addition of aldehydes and ketones?
Acidic solvent
What is the name for the molecule of addition of aldehydes and ketones?
Hydroxynitrile
Describe mechanism for addition of aldehydes and ketones?
(proponal to 2-hydroxybutanenitrile)
1) C is partially positive and O is partially negative. Lone pair from :C- moves to partially positive C
2) Lone pair on O attracts H+
Why can nucleophilic addition to aldehydes and asymmetrical ketones result in a racemic mixture of optical isomers?
- Bonding about a carbonyl group in an aldehyde and ketone is planar
- 50/50 chance of nucleophile attacking each side
- Results in equal mixture of optical isomers forming, racemic mixture
- Racemic mixture is not optically active as different isomers rotate polarised light the same amount so cancel out
What are aldehydes reduced into?
Primary alcohols
What are ketones reduced into?
Secondary alcohols
