Catalyst-Free Synthesis of α-Diazoketones in Water by Microwave Promoted Enaminone C=C Double Bond Cleavage

The reactions of enaminones with methyl sulfonyl azide providing alpha-diazoketones have been realized in pure water by means of microwave irradiation. Besides the green medium and energy source, the reactions benefit additional advantages of sustainability from the totally catalyst- and additive-free conditions. More significantly, the synthesis remarks the first successful application of the featured tandem [3+2] cyclo-addition and subsequent ring decomposition of the in situ generated 1,2,3-triazoline intermediate from enaminones and sulfonyl azide in the synthesis of alpha-diazoketones.