Chapter 30.SE, Problem 15MP

Interpretation Introduction

Interpretation:

The pericyclic reactions involved in the reaction shown are to be identified and a mechanism for the reactions is to be proposed.

Concept introduction:

In electrocyclic reactions cyclic alkenes or dienes react to yield acyclic conjugated dienes as poducts. A σ bond is broken, a new π bond is formed and some π bonds change their positions. The reactions are reversible.

In cycloaddition reactions two unsaturated molecules add to one another to yield a cyclic product.