Chapter 20, Problem 20.26P

Interpretation Introduction

Interpretation:

It is to be shown how to carry out the given synthesis.

Concept introduction:

The cyclic $\text{α,β-unsaturated}$ ketone can be produced from an aldol condensation reaction when the substrate possesses two carbonyl groups; both may be ketones, or one of them is either aldehyde or ketone. An acid chloride $\left(\text{RCOCl}\right)$, on treatment with a lithium dialkyl cuprates $\left({\text{R}}_{\text{2}}\text{CuLi}\right)$, produces the corresponding ketone $\left({\text{R}}_{\text{2}}\text{C=O}\right)$. Since lithium dialkylcuprate $\left({\text{R}}_{\text{2}}\text{CuLi}\right)$ a weak source of the nucleophile, ${\text{R}}^{-}$ does not react with ketones or aldehydes via direct addition. Esters and amides are more stable than acid chloride; thus they do not react with lithium dialkylcuprate $\left({\text{R}}_{\text{2}}\text{CuLi}\right)$. Thus, to convert amide or ester into a ketone, first convert them into an acid chloride.