Chapter 27, Problem 15E

Interpretation Introduction

Interpretation:

The reason for the faster ${\text{S}}_{\text{N}}2$ reaction of the molecule (a) as compared to that of the molecule (b) should be explained.

Concept introduction:

The nucleophilic substitution reaction $\left({\text{S}}_{\text{N}}2\right)$ is a single step substitution reaction in which electron rich species substitute leaving group. The attack takes place from the back side of the electrophilic center thus there is an inversion of the configuration takes place. Also, there is a single transition state because bond breaking and bond making occurs simultaneously.

The interaction between the axial groups present at the 1 and 3-carbon atom on a cyclohexane ring is known as $1,3-diaxial\text{ interaction}$. Bulky groups present at the axial position (1 and 3 positions) interact with each other and result in less stable cyclohexane ring or conformer.