Organic Photoredox-Catalyzed Synthesis of δ-Fluoromethylated Alcohols and Amines via 1,5-Hydrogen-Transfer Radical Relay

The hydrotrifluoromethylation of benzyl-protected homoallylic alcohol and amine derivatives catalyzed by 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) was developed. This reaction delivered delta-fluoromethylated free alcohols and amines with in situ deprotection of benzyl protecting group under mild irradiation conditions. 4CzIPN was found to be a competent metal-free photoredox catalyst for activating several types of fluoromethylation reagents including CF3SO2Cl, Togni's reagent, and 2-bromo-2,2-difluoroacetate via oxidative quenching and also CF3SO2Na through reductive quenching to allow direct hydrotrifluoromethylation of simple alkenes and Michael acceptors.