Chapter 5, Problem 39P

Interpretation Introduction

Interpretation:

It is to be explained that the $\text{bicyclo}\left[\text{2}\text{.2}\text{.1}\right]\text{heptan-1-ol}$ is relatively unreactive towards hydrogen halide.

Concept introduction:

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

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

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

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

The slow step in the ${\text{S}}_{\text{N}}\text{1}$ mechanism is formation of carbocation and it is the rate determining step.

The carbocation (positively charged carbon) is ${\text{sp}}^2$ hybridized and acquires planar structure.

The carbocation at bridgehead carbon is unstable.

The carbon atom which is a part of two or more rings in polycyclic compounds is as shown below: