Formation of diazoketones and azines by improved oxidation of ketohydrazones using Cu(acac) 2 as a catalyst

Abstract

An efficient Cu(acac) 2-catalyzed oxidation of ketohydrazones afforded the corresponding α-diazoketones or ketazines in high yields depending on the reaction conditions. However, the reaction of benzophenone hydrazone gave benzophenone azine without affording diphenyldiazomethane. The formation of azines is explained by the intermediacy of carbenoid generated by the Cu(acac) 2-catalyzed decomposition of diazo compounds.