Metal-free regioselective construction of 2-aryl-2H-tetrazol-5-yl difluoromethylene phosphonates

Three bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors with aryl diazonium salts has been accomplished under metal-free conditions with exclusive regioselectivity. This transformation provides practical access to a broad panel of 2-aryl-2H-tetrazol-5-yl difluoromethylene phosphonates, including the corresponding derivatives of amino acid (phenylalanine) and drug cores (Pomalidomide and Lapatinib fragment).