Electrocatalytic Synthesis of Substituted Pyrazoles via Hypervalent Iodine Mediated Intramolecular C-N Coupling

The electrochemical intramolecular cross-dehydrogenative C(sp(2))-H/N-H coupling of alpha,beta-unsaturated hydrazones resulting in substituted pyrazoles has been discovered. The process is catalyzed by hypervalent iodine species generated in situ through anodic oxidation of aryl iodide in fluorinated alcohol media. The formation of hypervalent iodine compound and its key role in the construction of a new C-N bond was confirmed with CV and NMR experiments. A wide range of substituted pyrazoles were obtained in yields ranging from 46% to 88%.

Automated summary

In this study, the electrochemical intramolecular cross-dehydrogenative C(sp(2))-H/N-H coupling of alpha,beta-unsaturated hydrazones resulting in substituted pyrazoles has been discovered. This process is catalyzed by hypervalent iodine species generated in situ through anodic oxidation of aryl iodide in fluorinated alcohol media. The formation of hypervalent iodine compound and its key role in the construction of a new C-N bond were confirmed with CV and NMR experiments. A wide range of substituted pyrazoles were obtained with yields ranging from 46% to 88%.