Chapter 28, Problem 44P

Interpretation Introduction

Interpretation:

The steps involved in the given reaction should be illustrated.

Concept introduction:

Pericyclic reactions are “ any concerted reaction in which bonds are formed or brocken in a cyclic transition state”.  There is a single transition state from start to finish, in contrast to a stepwise reaction.

In an electrocyclic reaction “one new sigma- bond is formed or brocken.”

Diels-Alder reaction is a cycloaddition reaction which is occurs between a conjugated diene and substituted alkene to form cyclohexene ring system.  This concerted reaction can be accelerated by heating or using some catalysts.

But in reverse Diels-Alder reaction, the six membered ring is break down to regenerate the diene and dienophile (substituted alkene) using high temperature.

Mechanism gives the step wise processes occurs in a particular reaction.