A new approach to the synthesis of annulated sulfur heterocycles
based on triflic anhydride-promoted cyclization of the hetaryl(aryl)
containing alkyl sulfides was elaborated. Smooth demethylation
of initially formed cyclic sulfonium salts by treatment with triethylamine
afforded a number of five-, six- and seven-membered fused sulfur
heterocycles. Unexpected ring opening took place in the reaction
of diethylamine with 5-membered sulfonium salts.
cyclizations - electrophilic aromatic substitutions - sulfur heterocycles - bicyclic compounds - sulfonylsulfonium
salts