Photocatalyzed Three‐Component Difluoroalkyl‐Halogenation of Electron‐Deficient Alkenes via a Halogen α‐Nucleophilic Addition

Abstract Here, we disclose a halogen α‐nucleophilic addition via photocatalytic oxidation of the in‐situ generated α‐carbonyl radical of amides or esters to corresponding α‐carbonyl cation. The α‐carbon radical is generated by the β‐addition of difluoroalkyl radical, formed by the photocatalytic reduction of BrCF 2 CO 2 R, to the α,β‐unsaturated amides/esters. This umpolung strategy enables an efficient three‐component difluoroalkyl‐halogenation of α,β‐unsaturated amides or esters with BrCF 2 CO 2 R and Cl / F ‐nucleophiles to produce diverse biologically important CF 2 ‐containing α‐halo‐1,5‐dicarboxylic derivatives under mild conditions.