Direct Synthesis of α-trifluoromethyl Ketone from (hetero)arylacetylene: Design, Intermediate Trapping, and Mechanistic Investigations

Regioselective addition across the alkynes has been achieved in a silver-catalyzed protocol utilizing Langlois reagent (CF3SO2Na) and molecular O2 to access medicinally active α-trifluoromethyl ketone compounds. This method was successful in producing α-trifluoromethyl ketone in heterocyclic scaffolds, which are incompatible with earlier strategies. Experimental findings suggest a mechanism involving α-styrenyl radical intermediate and 1-methyl-2-pyrrolidinone (NMP) solvent, which leads to crystallographically characterized N-methylsuccinimide. Isotope labeling, kinetic studies, and intermediate trapping further helped to gain insight into this energy-demanding process.