Chapter 10, Problem 10.15P

Interpretation Introduction

Interpretation:

The Williamson ether synthesis that would produce the given ether is to be devised.

Concept introduction:

Williamson ether synthesis is the formation of an ether $\text{R-O-}{\text{R}}^{\prime }$ by treating an alkyl halide with a salt of an alkoxide anion. This synthesis is used to synthesize both symmetric and unsymmetric ethers. The alkoxide salt dissociates in the solution to provide the strongly nucleophilic alkoxide anion ${\text{RO}}^{\text{-}}$, which favors an ${\text{S}}_{\text{N}}\text{2}$ reaction.

Since the nucleophile favors an ${\text{S}}_{\text{N}}\text{2}$ reaction, a primary alkyl halide works best as the substrate. Secondary alkyl halides give very poor yields while tertiary alkyl halides do not react as the steric hindrance due to the three alkyl groups on the electrophilic carbon prevent the nucleophile from approaching close enough to form a bond. Instead, an elimination reaction occurs as the alkoxide anion is also a strong base.