Question

Question: Explain why it is not possible to prepare tert-butyl phenyl ether using a Williamson ether synthesis.

Short answer

Answer

Tertiary-alkyl ethers exhibit steric hindrance, whether they are tertiary alkoxides or tertiary alkyl halides that are involved in Williamson ether synthesis. So, they inhibit the ${\mathrm{S}}_{\mathrm{N}}2$ mechanism involved in Williamson ether synthesis.

Step-by-step solution

Step-by-Step SolutionStep 1: Limitations of Williamson ether synthesis

One of the main drawbacks of Williamson ether synthesis is the preparation of tertiary ethers, as this reaction involves a bimolecular nucleophilic substitution reaction that completes in a single step.

Bulky groups hinder attacks from the backside during this process.

Tert-butyl phenyl ether

The structure of tert-butyl phenyl ether is as follows.

Tert-butyl phenyl ether

Williamson synthesis

The compound tert-butyl phenyl ether can be synthesized by two possible routes.

1. It involves the reaction between potassium phenoxide and tert-butyl chloride.

2. It involves tert-butoxide and chlorobenzene.

However, both routes involve tert-butyl chloride and tert-butoxide, respectively. So, the backside attack is not possible on the substrate molecule by the nucleophile.

Hence, the reaction is not possible.