The Regio- and Stereoselective Addition of Carbon Nucleophiles to Trifluoromethyl Phenylsulfanyl Acetylene: A Novel and Expeditious Approach to 3-Trifluoromethyl Furans.

A convenient generation of trifluoromethyl phenylsulfanyl acetylene was realized from 2-bromo-1-phenylsulfanyl-3,3,3-trifluoropropene. The reagent was reacted with carbanions to give (1E,3E)-2-trifluoromethylbutadienyl phenyl sulfides regio- and stereoselectively, which underwent intramolecular cyclization in decalin at 190°C or in acetic acid with 1,4-benzoquinone and sodium acetate to afford 3-trifluoromethyl-substituted furans in high yields.