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.