Visible-Light-Mediated Radical α-C(sp³)─H <i>gem</i>-Difluoroallylation of Amides with Trifluoromethyl Alkenes via Halogen Atom Transfer and 1,5-Hydrogen Atom Transfer

Direct <i>gem</i>-difluoroallylation at the α-carbonyl position is a challenging process by conventional methods. Herein we report the photocatalytic radical α-C(sp³)─H <i>gem</i>-difluoroallylation of amides with trifluoromethyl alkenes to access the target compounds with good yields and functional group tolerance. The mild and effective conditions allow <i>gem</i>-difluoroalkene motifs as carbonyl bioisosteres incorporated concisely to some complex molecules, including gemfibrozil and estrone derivatives, presenting great potential for late-stage functionalization of drugs, natural products, and bioactive intermediates. Mechanistic investigations suggest a radical pathway combining XAT and 1,5-HAT.