Chapter 20, Problem 20.13YT

Interpretation Introduction

Interpretation:

The mechanism for the reaction in Equation $\text{20-33}$ is to be determined.

Concept introduction:

Like hydride (${\text{H}}^{\text{-}}$) anions, alkyl anions (${\text{R}}^{\text{-}}$) can act as nucleophiles but not as leaving groups. The sources of ${\text{R}}^{\text{-}}$ are organometallic compounds such as alkyl lithium reagents ($\text{RLi}$), Grignard reagents ($\text{RMgX}$), and lithium dialkylcuprates (${\text{R}}_{\text{2}}\text{CuLi}$). Thus, as with hydride reagents, the product of nucleophilic addition-elimination reaction involving one of these organometallic reagents is not an acid derivative. In each case, two equivalents of the ${\text{R}}^{\text{’-}}$ nucleophile must add to the acid derivative to produce a tertiary alcohol.