Chapter 8, Problem 8.49P

Interpretation Introduction

Interpretation:

Whether the given nucleophilic substitution reaction proceeds by ${\text{S}}_{\text{N}}\text{1}$ or ${\text{S}}_{\text{N}}2$ mechanism is to be determined.

Concept introduction:

If the ${\text{S}}_{\text{N}}\text{1}$ reaction occurs at the chiral center, the product formed would be a racemic mixture i.e. a mixture of both stereo chemical configurations. The first step in the ${\text{S}}_{\text{N}}\text{1}$ reaction is the formation of a carbocation by the removal of the leaving group. The carbocation is planar; the nucleophile can approach the carbocation from either side and form a mixture of products with both $\text{R/S}$ isomers.

In ${\text{S}}_{\text{N}}2$ reaction, the nucleophile attacks the carbon having the leaving group from the opposite side of the leaving group which results in an inversion of the configuration at electrophilic carbon in the product.