Chapter 14.SE, Problem 63AP

Interpretation Introduction

Interpretation:

The observation that stereochemistry of the product formed when dimethylbutynedioate undergoes Diels-Alder reaction with (2E,4Z) 2.4-hexadiene is different from that obtained from (2E,4E) isomer is to be explained.

Concept introduction:

In Diels-Alder reaction, a dienophile reacts with a diene to yield a cyclic adduct. The reaction takes place through 1,4 addition of the dienophile into the diene through a cyclic transition state. These reactions occur rapidly with dienophiles having electron withdrawing substituent groups in conjugation with the double bond and if the diene adapts a s-cis conformation during the reaction.

To explain:

The observation that stereochemistry of the product formed when dimethylbutynedioate undergoes Diels-Alder reaction with (2E,4Z) 2.4-hexadiene is different from that obtained from (2E,4E) isomer.