Abstract
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•CF2HPh3PBr is a very effective source of difluoromethyl radicals under photoredox catalysis.•Direct difluoromethylation of 3-substituted indoles at the 2-position has been accomplished for the first time.•fac-Ir(ppy)3 is the most effective photoredox catalyst when using CF2HPh3PBr as the radical precursor.
A visible-light mediated approach to radical difluoromethylation of 3- and 3,5-substituted indoles was investigated using a readily synthesized difluoromethyl source, CF2HPPh3Br. Direct difluoromethylation of indoles in the two position is a rare feat in the literature. The reactions were conducted at room temperature, using Ir(ppy)3 as photocatalyst in acetone, to afford the 2-difluoromethyl indoles in relatively low to moderate yields.