Question

PART A. A 1:4 mixture of the (R) and (S)-enantiomers of compound A has a specific rotation of +40^o.

I) Calculate the enantiomeric excess for this mixture.

II) What is the specific rotation for the pure (R)-enantiomer?

III) Calculate the specific rotation for a 9:1 mixture of the (R)- and (S)-enantiomers of A.

PART B. The pure (S)-enantiomer of compound B has a specific rotation of +60^o.

I) Calculate the specific rotation for a 2:1 mixture of (R) and (S)-enantiomers of B.

PART C. Another sample of B has a specific rotation of -5^o.

I) What is the % (R)-B and %(S)-B present in the sample?