Electrochemical/I ^- Dual-Catalyzed Access to Sulfonated Pyrazoles under External Oxidant-Free Conditions

An electrochemical/I- dual-catalyzed access to sulfonated pyrazoles from pyrazolones and sodium sulfites under external oxidant free conditions has been developed. This established electrochemical reaction works smoothly under external oxidant-free conditions and has the advantages of good functional group tolerance, easy to gram scale synthesis, delivering up to 95% yield for 35 examples.