Photoredox-catalyzed direct C(sp2)–H difluoromethylation of enamides or heterocycles with [bis(difluoroacetoxy)iodo]benzene

Abstract

A photoredox-catalyzed direct C(sp²)–H difluoromethylation of enamides is accomplished by using easily accessible [bis(difluoroacetoxy)iodo]benzene as the CF₂H source. Diverse (E)-β-difluoromethylated enamides are obtained in moderate to good yields by using this protocol under visible light irradiation. A range of sensitive functional groups can be compatible under these conditions. Additionally, C(sp²)–H difluoromethylation of heterocycles is demonstrated. Moreover, this method is applied in the gram-scale difluoromethylation of a non-steroidal anti-inflammatory drug piroxicam precursor.