Chapter 10, Problem 10.48P

Interpretation Introduction

Interpretation:

The structures of the two ethers, apart from $\text{(1-ethylpropoxy)cyclopentane}$, produced when cyclopentanol and $\text{pentan-3-ol}$ were heated under acidic conditions, are to be drawn. The complete mechanism that shows how all three ethers are produced is to be drawn.

Concept introduction:

Two molecules of alcohol condense to form an ether when heated under acidic conditions. The reaction occurs via an ${\text{S}}_{\text{N}}\text{1}$ step because alcohols are weak nucleophiles.

Under acidic conditions, the hydroxyl ($-\text{OH}$) group is protonated, converting it into a good leaving group. The protonated hydroxyl group departs in the first step of the subsequent ${\text{S}}_{\text{N}}\text{1}$ reaction to produce a carbocation. Another molecule of alcohol then acts as a nucleophile and forms a $\text{C}-\text{O}$ bond to produce a protonated ether. Final deprotonation by a molecule of alcohol gives the final ether product. If only one alcohol is used, it acts as both substrate and nucleophile to give a symmetric ether. If a mixture of alcohols is used, a mixture of products is obtained. Each alcohol reacts with itself to produce one symmetric ether each. A reaction between one molecule each of the two alcohols produces one unsymmetric ether.