Chapter 10, Problem 10.6P

Interpretation Introduction

Interpretation:

The complete, detailed mechanism is to be drawn for the given reaction, and the major product is to be predicted.

Concept introduction:

Primary alkyl halides preferentially undergo ${\text{S}}_{\text{N}}\text{2}$ reactions because a primary carbocation is a very unstable species.

${\text{S}}_{\text{N}}\text{2}$ reactions are single-step, bimolecular reactions. The nucleophile attacks the electrophilic carbon in the substrate, and the leaving group departs at the same time. A subsequent deprotonation step is needed to form the final product if the nucleophile is a neutral species like an amine.

If the nucleophile is a primary amine and an excess of alkyl halide is used, the resultant secondary amine can still act as a nucleophile and attack another molecule of the alkyl halide. This can continue till a quaternary ammonium salt is formed if the alkyl halide is present in sufficient quantity.