Regioselective Synthesis of Trichloromethyl-Substituted Salicylates and Cyclohexenones by One-Pot Cyclizations of 1,3-Bis(trimethylsilyloxy)buta-1,3-dienes

A variety of 6-(trichloromethyl)salicylates (=2-hydroxy-6-(trichloromethyl)benzoates) were prepared by TiCl₄-mediated cyclization of 1,3-bis(trimethylsilyloxy)buta-1,3-dienes with 1,1,1-trichloro-4,4-dimethoxybut-3-en-2-one. The employment of trimethylsilyl trifluoromethanesulfonate (Me₃SiOTf) as Lewis acid resulted in the formation of trichloromethyl-substituted cyclohexenones. The cyclizations proceeded with good-to-very-good regioselectivities.