Chapter 22.16, Problem 22.48P

(a)

Interpretation Introduction

Interpretation:

The validation of the fact that the given ester cannot be synthesized by malonic ester synthesis is to be stated with an explanation.

Concept introduction:

Deprotonation of malonic ester giveenolate ion. This enolate ion is alkylated by an unhindered alkyl halide, tosylates or any other electrophilic species through ${\text{S}}_{\text{N}}\text{2}$ displacement to give alkylated diethyl malonate. It will undergo hydrolysis to give substituted acetic acid.

(b)

Interpretation Introduction

Interpretation:

The acid-base reaction between LDA and the given ester is to be stated and the direction of equilibrium is to be predicted.

Concept introduction:

LDA (Lithium Di-isopropyl Amide) is a strong base with a molecular formula, ${\left[{\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{CH}\right]}_{\text{2}}\text{NLi}$. It is most commonly used in the formation of enolates. Enolate acts as a useful nucleophile that participates in ${\text{S}}_{\text{N}}\text{2}$ reaction as well as aldol reaction.

(c)

Interpretation Introduction

Interpretation:

The method of preparation of given compound using malonic ester synthesis is to be stated.

Concept introduction:

Deprotonation of malonic ester give enolate ion. This enolate ion is alkylated by an unhindered alkyl halide, tosylates or any other electrophilic species through displacement to give alkylated diethyl malonate. It will undergo hydrolysis to give substituted acetic acid.