An Efficient and Improved Method for the Synthesis of Bis(arylmethylidene)thiopyranones

Double crossed aldol condensation of a variety of aromatic aldehydes with tetrahydrothiopyran-4-one in the presence of N-(trimethylsilyl)diethylamine and 5 M lithium perchlorate in diethyl ether at room temperature is described. Excellent yields of 3,5-bis(arylmethylidene)thiopyranones are achieved in a facile onepot general procedure.