Visible-Light-Induced Radical Defluoroborylation of Trifluoromethyl Alkenes: An Access to gem-Difluoroallylboranes

A photoredox-catalyzed defluoroborylation of trifluoromethyl alkenes with N-heterocyclic carbene boranes is described for the synthesis of gem-difluoroallylboranes. This protocol exhibits a broad substrate scope and good functional group compatibility, which enables the late-stage functionalization of structurally complex compounds. Further transformations of the defluoroborylation products to valuable CF2-containing molecules are also demonstrated.