Electrochemical diazenylation of active methylene compounds with aryldiazonium salts: efficient synthesis of β-dicarbonyl benzoylhydrazones

In this study, an electrochemical synthetic strategy is reported for the diazenylation of various active methylene compounds through their reaction with aryldiazonium salts, leading to the efficient formation of β-dicarbonyl benzoylhydrazones. The reaction efficiency and selectivity are significantly enhanced by the promotion of LiBr, along with the rational selection of electrode materials to effectively suppress the formation of a solid electrolyte interphase (SEI) layer on the electrode surface. The developed methodology exhibits remarkable substrate versatility, accommodating a broad range of substrates including aliphatic, cyclic, and aromatic diketones, as well as malononitrile and malonate derivatives. This work provides a green, cost-effective, and highly efficient approach for the synthesis of valuable benzoylhydrazone derivatives.