Heterocyclic mesomeric betaines. Part 6. Synthesis and a cycloaddition of a hetero derivative of the 1-methylenephenalene-3-methide anion
Abstract
Synthesis of the cross-conjugated heterocyclic mesomeric betaine 4 is reported. This mesomeric betaine 4 is isoconjugate with the odd alternant hydrocarbon anion 5(R = Ph). Cycloaddition of the betaine 4 with dimethyl acetylenedicarboxylate yields the 1,4-cycloadduct 14.