Mn(III)-Catalyzed Radical Cyclization for the Phosphorylation of Heteroarenes via the Reactions of Diphenylphosphine Oxide with Isocyanides/Heteroarenes

The development of operationally simple and environmentally benign synthetic strategies for constructing phosphorus-substituted heterocycles is highly valuable in organophosphorus chemistry. Herein, we report a straightforward and green radical cascade cyclization of diphenylphosphine oxide with isocyanides or heteroarenes for the synthesis of phosphorylated heteroarenes with high atom economy. With air as a green oxidant and ethanol as the solvent, without additional oxidants or bases, this one-pot protocol exemplifies the principles of green chemistry, enabling the construction of C–P and C–C bonds using an inexpensive, commercially available and low-toxicity catalyst. Studies on electron paramagnetic resonance and control experiments indicated that manganese(III) salt and O2 act in concert to achieve radical cascade cyclization, with superoxide radical anion (O2•–) contributing to this reaction.