Chapter 20, Problem 20.54P

Interpretation Introduction

Interpretation: The lettered products (A-D) in the given reaction scheme are to be filled.

Concept introduction: CBS reagents are chiral reducing agent, which selectively reduce keto compounds into corresponding alcohols. These are of two types; (R)-CBS, and (S)-CBS. The (R)-CBS reagent provides ${\text{H:}}^{-}$ from behind to convert keto compounds into (S) isomer of an alcohol as the major product. The (S)-CBS reagent provides ${\text{H:}}^{-}$ from front to convert keto compounds into (R) isomer of an alcohol as the major product.