Chapter 6, Problem 49P

Interpretation Introduction

Interpretation:

The detailed mechanism for the given reaction is to be proposed.

Concept introduction:

Reaction mechanism is the step by step sequence of elementary reactions.

Reaction sequences involve conversion of one functional group to another, which may also require addition or loss of carbon from the reactant.

These sequences involve a number of steps carried out by different reagents. Sometimes different reagents give the same products.

Electrophiles are electron-deficient species, which has positive or partially positive charge. Lewis acids are electrophiles, which accept electron pair.

Nucleophiles are electron-rich species, which has negative or partially negative charge. Lewis bases are nucleophiles, which donate electron pair.

Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a functional group is substituted by any other functional group is called substitution reaction.

Nucleophilic substitution reaction is a reaction in which an electron-rich nucleophile attacks the positive or partial positive charge of an atom or a group of atoms to replace a leaving group.

An ${\text{S}}_{\text{N}}\text{2}$ reaction is the nucleophilic substitution reaction in which two components are involved in the rate determining step. ${\text{S}}_{\text{N}}\text{2}$ reaction occurs in one step.

An ${\text{S}}_{\text{N}}1$ reaction is the nucleophilic substitution reaction in which one component is involved in the rate determining step. ${\text{S}}_{\text{N}}1$ reaction occurs in two step.

The involvement of nearby nucleophile substituent to the reaction center in the substitution process is known as neighboring group participation.

Such participation results in an increase of rate of reaction. The phenomenon is described as Anchimeric assistance.

In this participation, two ${\text{S}}_{\text{N}}\text{2}$ reactions are occurred, which results in two inversion of configuration, that is, overall retention of configuration.