One-Pot Reaction of α-Diazo Phosphonates via Iodine-Catalyzed Cascade Radical Aerobic Oxidation and C-P Bond Cleavage

A one-pot transformation of α-diazophosphonates has been developed through an iodine-catalyzed cascade radical aerobic oxidation followed by thin-layer chromatography silica-gel-promoted C-P bond cleavage, affording aromatic carboxylic acids in up to an 82% yield. Control experiments and density functional theory calculations indicate that the I2-catalyzed aerobic oxidation reaction proceeds via generation of the iodoalkyl radical, coupling with molecular oxygen, hydrogen atom abstraction from dichloromethane, and C-I bond cleavage to deliver the corresponding α-keto phosphonates. This metal-free protocol features mild reaction conditions, operational simplicity, and scalability. Moreover, it reveals a new reaction mode of α-diazophosphonates.