Catalytic Bismuth(V)-Mediated Oxidation of Hydrazones into Diazo Compounds.

A new bismuth(V) oxidative catalytic system has been developed and applied for the conversion of hydrazones into diazo compounds. With the use of low catalytic amounts of Ph 3 Bi and AcOH with NaBO 3 ·H 2 O as a terminal oxidant, the in situ formation of Ph 3 Bi(OAc) 2 is capable of oxidizing hydrazones in excellent yields. The reaction was applied for the synthesis of diazocarbonyls and 2,2,2-trifluoromethyl diazoalkanes in good to excellent yields.