Reaction of pyridinium disubstituted methylides with diphenylcyclopropenethione

Diphenylcyclopropenethione undergoes nucleophilic attack by pyridinium disubstituted ylides 1a-1e to produce the corresponding 2-pyranthione 3a , 2-pyrone 4a or 4c , thiopyran-2-one 6a, 6b, 6d or 6e , and/or 5H-thieno3,2-b]thiopyran 5a .