Chapter 22, Problem 86IP

Interpretation Introduction

Interpretation: A mechanism for the formation of the product has to be provided.

Concept Introduction:

Diels-Alder reaction is a [4+2]-cycloaddition of a conjugated diene and a dienophile (an alkene or alkyne), an electrocyclic reaction that involves the 4 π-electrons of the diene and 2 π-electrons of the dienophile. The driving force of the reaction is the formation of new σ-bonds, which are energetically more stable than the π-bonds. Typically, Diels-Alder reaction works best when either the diene is substituted with electron-donating groups (like -OR, -NR₂, etc) or when the dienophile is substituted with electron-withdrawing groups (like -NO₂, -CN, -COR, etc).

To find: Provide a mechanism for the formation of the product

Derive the intermediate benzyne by heating