Chapter 20, Problem 20.9P

Interpretation Introduction

Interpretation: The carbonyl compound and CBS reagent are needed to prepare $X$ are to be identified.

Concept introduction: CBS reagents are used to reduce the enantioselective carbonyl compounds. They are called enantioselective carbonyl reduction. The $\left(\text{S}\right)-\text{CBS}$ reagent gives $R-\text{alcohol}$ as a major product. The $\left(R\right)-\text{CBS}$ reagent gives $S-\text{alcohol}$ as a major product.