Chapter 7, Problem 39PP

Interpretation Introduction

Interpretation: The preparation of given alkyne through ${\text{S}}_{\text{N}}2$ reaction mechanism is to be verified for the given reaction.

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both (substrate and nucleophile) of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays a major role in ${\text{S}}_{\text{N}}2$ reaction. If the substrate consists of more substitution the rate of the reaction becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate it depends on steric factor that if more groups attached near the leaving group the reactivity become slower.

Leaving group: it is the fragment that leaves the chemical compound with pair of electrons in a heterolytic bond cleavage.

Example