Chapter 20, Problem 20.49P

Interpretation Introduction

(a)

Interpretation:

How the given transformation can be carried out is to be explained.

Concept introduction:

An ester can be converted to a tertiary alcohol by reacting it with ${\text{RLi (excess), then H}}_{\text{3}}{\text{O}}^{+}$. The ${\text{R}}^{-}$ is a nucleophile and adds to the carbonyl group of ester and reduces to ketone by elimination of methoxide ion. This ketone is further reduces to a tertiary alcohol, followed by protonation using ${\text{H}}_{\text{3}}{\text{O}}^{+}$.

Interpretation Introduction

(b)

Interpretation:

How the given transformation can be carried out is to be explained.

Concept introduction:

An acid chloride can be converted to the corresponding ketone by reacting it with a lithium dialkylcuprate $\left({\text{R}}_{\text{2}}\text{CuLi}\right)$. The only one alkyl group from $\left({\text{R}}_{\text{2}}\text{CuLi}\right)$ acts as a nucleophile, adds to the acid derivative, and then undergoes elimination of the chloride ion to produce the ketone.

Interpretation Introduction

(c)

Interpretation:

How the given transformation can be carried out is to be explained.

Concept introduction:

An acid chloride can be converted to a tertiary alcohol by reacting it with ${\text{RMgBr (excess), then H}}^{+}$. $\text{RMgBr}$ is the Grignard’s where ${\text{R}}^{-}$ acts as a nucleophile and adds to the carbonyl group of acid chloride and reduces to ketone by elimination of chloride ion. This ketone is then reduced to a tertiary alcohol, followed by protonation using ${\text{H}}^{+}$.

Interpretation Introduction

(d)

Interpretation:

How the given transformation can be carried out is to be explained.

Concept introduction:

An acid anhydride can be converted to a tertiary alcohol by reacting it with ${\text{RMgBr (excess), then H}}^{+}$. $\text{RMgBr}$ is the Grignard’s where ${\text{R}}^{-}$ acts as a nucleophile, adds to carbonyl group of acid anhydride, and reduces to ketone. This ketone is then reduced to a tertiary alcohol, followed by protonation using ${\text{H}}^{+}$.