Chapter 30.SE, Problem 24AP

Interpretation Introduction

Interpretation:

The observation that cyclohexadecaoctaene isomerizes to two different isomers depending on reaction conditions is to be explained indicating whether each reaction is conrotatory or disrotatory.

Concept introduction:

An electrocyclic reaction involves the cyclization of a conjugated acyclic system. These reactions are reversible and are highly stereospecific.

In elecrocyclic reactions involving even number of electron pairs, a thermal reaction occurs in conrotatory manner and a photochemical reaction occurs in disrotatory manner.

In elecrocyclic reactions involving odd number of electron pairs, a thermal reaction occurs in disrotatory manner and a photochemical reaction occurs in conrotatory manner.

To explain:

The observation that cyclohexadecaoctaene isomerizes to two different isomers depending on reaction conditions.

To indicate:

Whether each reaction is conrotatory or disrotatory.