Chapter 18, Problem 18.7YT

Interpretation Introduction

Interpretation:

The hemiacetal and acetal in the mechanism in Equation 18-13 are to be identified. Also the steps that make up an ${\text{S}}_{\text{N}}\text{1}$ reaction are to be circled.

Concept introduction:

If an aldehyde or ketone is treated with a large excess of an alcohol under acidic conditions, then the hemiacetal produced from nucleophilic addition reacts further to form an acetal, in which two alkoxy (RO) groups are bonded to the same carbon. A hemiacetal group is an ${\text{R}}_{\text{2}}\text{C}\left(\text{OH}\right)\left(\text{OR}\right)$ or $\text{RCH}\left(\text{OH}\right)\left(\text{OR}\right)$. An acetal group is ${\text{R}}_{\text{2}}\text{C}{\left(\text{OR}\right)}_{\text{2}}$ or $\text{RCH}{\left(\text{OR}\right)}_{\text{2}}$.