Chapter 9, Problem 9.53P

Interpretation Introduction

Interpretation:

The given substrates are to be ranked in order from the slowest ${\text{S}}_{\text{N}}2$ reaction rate to the fastest.

Concept introduction:

As the number of alkyl groups on the carbon atom to which the leaving group is bonded increases, the ${\text{S}}_{\text{N}}2$ reaction rate sharply decreases. With greater steric hindrance surrounding the $\text{C-L}$ carbon, it becomes more difficult for the nucleophile to attack, and the ${\text{S}}_{\text{N}}2$ rate decreases. When a leaving group is bonded to an alkene or an alkyne carbon, ${\text{S}}_{\text{N}}2$ reactions are hindered by repulsion between the negatively charged $\text{π}$ electron cloud and the incoming nucleophile.