SYNTHESIS OF BETA-DIMETHYLSULFONIUM-SUBSTITUTED AND BETA-METHYLTHIO-SUBSTITUTED VINYL TRIFLATES BY REACTION OF ACETYLENES WITH DIMETHYL SULFIDE DITRIFLATE

A one-pot synthesis of beta-dimethylsulfonium-substituted vinyl trifla tes by the reaction of dimethyl sulfide ditriflate with acetylenes is described. beta-Dimethylsulfonium-substitute vinyl triflates were foun d to exhibit unusual reactivity towards nucleophiles resulting in deme thylation of sulfonium salts, but not substitution of triflate. Demeth ylation of these sulfonium salts with diethylamine gave the correspond ing beta-methylthio-substituted vinyl triflates. The possibility of th iophene derivative synthesis via triflic anhydride promoted cyclizatio n of sulfoxide was studied.