The Iron-Catalyzed Oxidation of Alkynesu1,2-Dione Formation Versus Oxidative CleavageuA Matter of Temperature

The iron-catalyzed oxidation of a variety of alkynes with hydrogen peroxide as the oxidant was examined in detail. Various reaction parameters were investigated in the oxidation of diphenyl acetylene. The best catalytic performance was observed for a combination of FeCl3 with 4-dimethylamino pyridine (DMAP) as the ligand, yielding various 1,2-diones in excellent yields and selectivities at room temperature. Moreover, by subsequently increasing the reaction temperature to 60?degrees C, a selective oxidative cleavage was observed, resulting in carboxylic acid derivatives.