Chapter 13.10, Problem 4LTS

Interpretation Introduction

Interpretation: The product along with its mechanism has to be predicted.

Concept Introduction:

Ring opening reactions occur when an Epoxide is attacked by strong nucleophile. The mechanism of transformation generally occurs in two steps as nucleophilic attack and proton transfer.

In first step, hydroxide acts as nucleophile and helps in opening of ring by ${\text{S}}_{\text{N}}\text{2}$ process.

In second step, the alkoxide ion is protonated by Water.

These kinds of reactions involve in two significant features called as regiochemistry and stereochemistry.

1. 1) Regiochemistry: The nucleophilic attack is seen at the less substituted(less hindered) position in an unsymmetrical epoxide. The less hindered position (steric effect) is expected from ${\text{S}}_{\text{N}}\text{2}$ process.
2. 2) Stereochemistry: Inversion of configuration is observed when nucleophilic attack is seen at chirality center. This steric effect is also expected from ${\text{S}}_{\text{N}}\text{2}$ process.