Metal-free Lewis-acid-catalyzed divergent trifluoromethylselenolation of alkynes: construction of α-trifluoromethylselenolated ketones and alkynes

Abstract

Herein, we have developed a mild and efficient Lewis-acid-catalyzed divergent trifluoromethylselenolation of alkynes. With trifluoromethyl selenoxide as the electrophilic trifluoromethylselenolation reagent, the terminal and internal aliphatic alkynes could be selectively transferred to α-trifluoromethylselenolated ketones with boron trifluoride diethyl etherate (BF₃·Et₂O) as the catalyst. In contrast, the trimethylsilyl (TMS)-substituted alkynes could be selectively converted to trifluoromethylselenolated alkynes with trifluoromethanesulfonic anhydride (Tf₂O) as the catalyst. These transformations showed good functional group tolerance. An electrophilic trifluoromethylselenolation pathway was proposed based on the preliminary results.