Chapter 23, Problem 23.90P

Interpretation Introduction

Interpretation:

The structure of compounds A-H in the given synthesis is to be determined.

Concept introduction:

The given synthesis is carried out by bromination of benzene. Bromine is an ortho/para director, but the para isomer is the major product because $\text{Br}$ and ${\text{CH}}_{\text{3}}$ have some steric bulk. This will give a para substituted bromobenezene. The ${\text{CH}}_{\text{3}}$ group is oxidized by ${\text{KMnO}}_{\text{4}}$ to give carboxylic acid, which is further reduced by ${\text{LiAlH}}_{\text{4}}$ to give alcohol, which oxidizes to give aldehyde. The aldehyde reacts with acetone in a crossed Aldol addition to produce the $\text{α,β-}$ unsaturated carbonyl compound, which undergoes conjugate nucleophilic addition to form the final compound. The combination of all the processes leads to the given synthesis.