Photoredox-Enabled Direct and Three-Component Difluoroalkylative Modification of N-Aryl Glycinates

A Cu(I) photoredox-enabled reaction that selectively incorporates a difluoroalkyl group into N-aryl glycine derivatives has been established. Using a bench-stable [Ph3PCF2H]+Br- salt, the -CF2H group could be installed either directly on the α-carbon of the glycine backbone or in a three-component fashion using an alkene as a bridge. A series of glycine derivatives have been evaluated, providing access to diverse unnatural amino esters and dipeptides with a -CHF2 unit. The studies of the compatibility of other perfluorinated alkyl radical precursors showed that the selectivity of direct α-coupling is closely associated with the electronic property of the radical, while the three-component reaction works well in most cases.