Copper-catalyzed trifluoromethylation of vinyl azides with BrCF2CO2K: synthesis of α-trifluoromethyl ketones without external fluoride sources.

Herein, we disclose a copper(I)-catalysed trifluoromethylation of vinyl azides with BrCF2CO2K and water, affording α-trifluoromethyl ketones without an external fluoride source. BrCF2CO2K serves as both a difluorocarbene precursor and an internal fluoride reservoir, enabling net CF3 incorporation through a copper-difluorocarbene pathway. This mild protocol shows broad substrate scope and good functional-group tolerance, establishing a practical method without an additional fluorine source to α-trifluoromethyl ketones. Product derivatizations and mechanistic observations further demonstrate its synthetic utility and support the involvement of a copper-difluorocarbene intermediate, thereby expanding the synthetic potential of metal difluorocarbene chemistry.