New Electrophilic Trifluoromethylating Agents

Synthetic routes to S-(trifluoromethyl)phenyl-4-fluorophenylsulfonium triflate (8), S-(trifluoromethyl)phenyl-2,4-difluorophenylsulfonium triflate (9), S-(trifluoromethyl)phenyl-3-nitrophenylsulfonium triflate (10), and S-(trifluoromethyl)-4-fluorophenyl-3-nitrophenylsulfonium triflate (11) are described. They are stable molecules and conveniently prepared by treating phenyl trifluoromethyl sulfoxide with benzene and its derivatives. These novel electrophilic trifluoromethylating agents react under mild conditions with a variety of aromatic rings (p-hydroquinone, pyrrole, and aniline) to give trifluoromethylated compounds (2-trifluoromethyl-p-hydroquinone, 2-trifluoromethylpyrrole, 2-trifluoromethylaniline, and 4-trifluoromethylaniline) in moderate to high yields. The electrophilic trifluoromethylating potential can be altered by placing electron-withdrawing substituents on the benzene rings.