Electrochemically enabled synthesis of multi-substituted pyrazoles via a radical cyclization cascade†

Despite the widespread applications of aryl diazonium salts, capturing both aryl radicals and aryl diazo radicals simultaneously remains a significant challenge due to the extreme instability of the diazonium radicals. Herein, we report a mild and efficient electrochemical reduction approach employing aryl diazonium salts as dual synthons to synthesize valuable multi-substituted pyrazoles for the first time. Furthermore, this method demonstrates significant practical potential through the modification of pharmaceutical intermediates, and a two-step one-pot approach that utilizes anilines as starting materials.