Chapter 5, Problem 44P

Interpretation Introduction

Interpretation:

The stepwise mechanism of the formation of $\text{Bromomethylcycloheptane}$ is to be written and the mechanism is to be classified.

Concept introduction:

The reaction of methyl and primary alcohols with hydrogen halide mostly proceeds through ${\text{S}}_{\text{N}}\text{2}$ mechanism.

The reaction of tertiary alcohol with hydrogen halide proceeds through ${\text{S}}_{\text{N}}\text{1}$ mechanism.

The ${\text{S}}_{\text{N}}\text{2}$ reaction is the bimolecular nucleophilic substitution reaction whose rate determining step involves two reactants (both electrophile and nucleophile).

The ${\text{S}}_{\text{N}}\text{1}$ reaction is the unimolecular nucleophilic substitution reaction that means that the rate determining step involves only one reactant.

Formation of carbocation is the rate determining step in ${\text{S}}_{\text{N}}\text{1}$ mechanism.

The nucleophile (halide ion) attacks on the electrophilic carbon from opposite side of hydroxyl group (i.e. backside attack) in ${\text{S}}_{\text{N}}\text{2}$ mechanism.

The position of leaving group in reactant and that of nucleophile in the product are same in case of ${\text{S}}_{\text{N}}\text{2}$ mechanism and it may be same or different in case of ${\text{S}}_{\text{N}}\text{1}$ mechanism depending on the stability of carbocation.