Visible-light-driven radical cascade cyclization of 4-( N -alkyl- N -acrylamido)coumarins: access to difluoroalkylated 4,5-fused coumarins and coumarin[4,3- b ]pyridinones

An efficient and practical visible-light-driven cascade difluoroalkylation/cyclization of 4-acrylaminocoumarins has been developed using readily accessible [Ph 3 PCF 2 H] + Br − as the difluoroalkyl radical precursor.