Chapter 7, Problem 58P

Interpretation Introduction

Interpretation:The structure of most likely product for the indicated reaction should be written.

  

Concept introduction: Carbocation formation is relatively slower than acid-base reactions. Carbocations generated from alkyl halides have two fates; they can be either trapped by nucleophiles to give substitution product or may deprotonate to yield a small amount of alkene.

Unimolecuar substitution or ${\text{S}}_{\text{N}}1$ proceeds via two-step mechanism. The first slow step that determines rate is the removal of leaving group from the substrate haloalkane and generates a carbocation. Since the rate is only governed by substrate alone and no other nucleophile or solvent it is termed as unimolecuar substitution. The final step is attack of nucleophile on carbocation generated and formation of racemic products.

A general ${\text{S}}_{\text{N}}1$ reaction mechanistic pathway is illustrated below:

  

The most likely mechanisms for different kinds of alkyl halides reactions with various nucleophiles is given as follows: