Reactions of α,β-Unsaturated Thiones with Diphenylcydopropenone and Diphenylcydopropenethione

2-(Arylmethylene)tetralin-1-thione and 1-aryl-3-phenyl-2-propene-1-thione (thiochalcone) reacted with diphenylcydopropenone across the =C–CO bond giving a thiophene derivative and a polysubstituted phenol with the arylketene/sulfur elimination, whereas the reaction with diphenylcydopropenethione took place at the C=S bond affording a spiro compound.