Chapter 19, Problem 19.78P

Interpretation Introduction

Interpretation:

It is to be shown how to synthesize the given compound using propanal as only carbon source.

Concept introduction:

The protection of the alcoholic OH group is done by the treatment with silyl chloride (either $\text{TMS-Cl}$ or $\text{TBDMS-Cl}$) the protected form of alcohol is silyl ether ($\text{R-O-Si-}$). For deprotection of silyl ether, ${\text{Bu}}_{\text{4}}{\text{N}}^{\text{+}}{\text{F}}^{\text{-}}$ or concentrated $\text{HF}$ acid is used. Sodium borohydride (${\text{NaBH}}_{\text{4}}$) is good reducing and reduces aldehyde and ketone to corresponding primary and secondary alcohol respectively. Alcohol on treatment with ${\text{PBr}}_{\text{3}}$ or ${\text{PCl}}_{\text{3}}$ corresponding alkyl halide is formed via back to back ${\text{S}}_{\text{N}}\text{2}$ reaction. The feature of this reaction is it occurs under the mild condition with inversion of configuration. Alkyl halide on treatment with solid magnesium metal corresponding Grignard reagent is formed. Grignard reagent on treatment with an aldehyde corresponding secondary alcohol is formed as the product during the workup step.