Photocatalytic Keto- and Amino-Trifluoromethylation of Alkenes.

Efforts to develop alternatives to triflic anhydride (Tf 2 O) as a trifluoromethylation reagent continue due to its limitations, including volatility, corrosiveness, and moisture sensitivity. Described herein is the use of a trifluoromethylsulfonylpyridinium salt ( TFSP ), easily obtained by a one-step reaction of Tf 2 O with 4-dimethylaminopyridine, as a reagent for the trifluoromethylative difunctionalization of alkenes by photoredox catalysis. DMSO and CH 3 CN are suitable solvents for achieving keto- and amino-trifluoromethylation of alkenes, respectively, with good functional group tolerance.