Addition reactions of heterocyclic compounds. Part 71. The formation of 1,3a,3b,4,6a,6b-hexahydrocyclopenta[3,4]cyclobuta[1,2-b]pyrroles from dimethyl acetylenedicarboxylate and 1-aryl-1,4-dihydropyridines

Abstract

1-Aryl-1,4-dihydropyridines combine with dimethyl acetylenedicarboxylate to form tetramethyl 1-aryl-1,3a,3b,4,6a,6b-hexahydrocyclopenta[3,4]cyclobuta[1,2-b]pyrrole-3,3a,6,6a-tetracarboxylates, the structures of which were deduced from their ¹H, ¹³C n.m.r., and mass spectra. The mode of formation of the adducts is discussed.