High pressure and thermal Diels–Alder reaction of 2-vinyl-benzo[b]furan and 2-vinyl-benzo[b]thiophene. Synthesis of new condensed heterocycles

A new preparation of 2-vinyl-benzo[b]furan and 2-vinyl-benzo[b]thiophene is described. Diels–Alder reactions of these dienes with 3-nitro-2-cyclohexen-1-one and 2-inden-1-one was examined under thermal and high pressure conditions. The reaction products have been converted to multi-ring heteroaromatic compounds.