Synthesis of trifluoromethyl-substituted salicylates by cyclocondensation of 1,3-bis(silyloxy)-1,3-butadienes with 4,4-dimethylthio-l,1, 1 -trifluorobut-3-en-2-one

摘要

A formal [3+3] cyclocondensation of 1,3-bis(silyl enol ethers) with the little-known 4,4-dimethylthio-1,1,1 -trifluorobut-3-en-2-one was studied. In contrast to 4,4-dimethoxy-l ,1,1 -trifluorobut-3-en-2-one, this α-oxoketene dithioacetal reacts with 1,3-bis(trimethylsilyloxy)-1,3-butadienes in the presence of TiCl4 to give mainly 6-methylthio-4-(trifluorornethyl)salicylates via 1,2-addition. The scope and limitations of the reaction are discussed.