ene-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.
Chemistry of .alpha.,.beta.-unsaturated thione dimers. 3. Reactions of thiochalcones and 2-arylidene-1-thiotetralones with cumulenes containing a carbon-carbon double bond