Alternative modes of addition of dienophiles to vinylcyclopropane systems

Abstract

Two alternative modes of addition to vinyl-cyclopropane systems are here described for each of two dienophiles: tetracyanoethylene is shown to react either via[2 + 2] or by [2 + 4] cycloadditions; and dimethyl acetylenedicarboxylate reacts either by the ‘ene’ route or by way of insertion to the double bond.