Facile access to trifluoromethyl propargyl alcohol by metal-free transfer hydrogenation and cyanation of alkynyl ketones†

Abstract

We report an efficient synthetic route to the metal-free hydroboration and cyanosilylation of a wide range of alkynyl trifluoromethyl ketones using pinacolborane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane) and trimethylsilyl cyanide under mild reaction conditions at ambient temperature. These highly effective hydroboration and cyanosilylation reactions lead to the corresponding alkynyl trifluoromethyl propargyl alcohols after hydrolysis. In addition, trifluoromethyl (CF₃) group-based pharmaceutically active enflicoxib analogs were synthesized from propargyl alcohol.