Enantiomers from Carbonyl Compounds Flashcards
1
Q
What reaction mixture is formed from the 2 enantiomers after reduction of carbonyl compounds with cyanide? What are its proportions in terms of ratios of enantiomers?
A
- Racemic mixture
- 50/50 since there is a 50/50 chance of the attack happening on either side
2
Q
What enantiomer is formed when cyanide ions react with carbonyls?
A
- :CN- attacks either side of the carbonyl
- The 2 different sides can cause 2 different enantiomers to be formed
3
Q
What happens in the racemic mixture in regard to plane polarised light?
A
- Enantiomers in a racemic mixture rotate plane polarised light
- But in opposite reactions
- Since there is a 50/50 mixture, the opposite rotations cancel out
- So no effect on plane polarised light in racemic mixtures
- Ie. Optical rotation is 0
4
Q
How can we test if mixtures are racemic?
A
- If there is an effect on plane polarised light, then the sample is not racemic
- If the sample contains enantiomers of chiral compounds and there is 0 effect on polarised light, then the reaction mixture must be racemic
5
Q
What is Chiral C?
A
Carbon attached to 4 different species.