Organic photoredox catalytic α-C(sp3)–H phosphorylation of saturated aza-heterocycles

Abstract

A metal-free C(sp³)–H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Brønsted acid catalyses was established under mild conditions. This protocol provided straightforward and economic access to a variety of valuable α-phosphoryl cyclic amines by using commercially available diarylphosphine oxide reagents. In addition, the D–A fluorescent molecule DCQ was used for the first time as a photocatalyst and exhibited an excellent photoredox catalytic efficiency in this transformation. A series of mechanistic experiments and DFT calculations demonstrated that this transformation underwent a sequential visible light photoredox catalytic oxidation/nucleophilic addition process.