Features of Phosphorylation of Diaryl Ketones with Red Phosphorus in the KOH–DMSO(H2O) System under Microwave Assistance

A distinctive feature of the microwave-assisted phosphorylation of diaryl ketones with red phosphorus in the KOH–DMSO(H2O) system is the very high rate of the process (complete conversion of phosphorus at 140°C is achieved for 1 min versus 50 min with conventional heating at 140°C). The main reaction products are potassium salts of bis(diarylmethyl)phosphoric acids (7–34%), as well as diaryl carbinols and diaryl methanes with overall yields of 29–84%. It was shown that the microwave-assisted reaction begins with a nucleophilic attack on the carbonyl group by a P-centered anion, in contrast to its purely thermal variant, for which the anion-radical nature was previously established.