Chapter 8, Problem 8.73P

Interpretation Introduction

Interpretation:

A mechanism is to be proposed for the given reaction under conditions that favor an ${\text{S}}_{\text{N}}\text{1}$ reaction.

Concept introduction:

An ${\text{S}}_{\text{N}}\text{1}$ reaction mechanism consists of two steps. The first step involves only the substrate. The leaving groups break off, taking the bond electron pair with it. This results in the formation of a carbocation intermediate. The carbocation formed may be subject to a rearrangement if a $\text{1, 2-hydride}$ or a $\text{1, 2-methyl}$ shift can convert it to a more stable carbocation.

In the second step, the nucleophile uses a lone pair on an atom like O to form a bond with the carbocation. If the incoming nucleophile is an uncharged specie like water or alcohol, a final deprotonation step involving any base present in the reaction mixture is necessary for the formation of the final product.