Zinc‐Catalysed [3+2] Cycloaddition of Enaminone with Tosylhydrazide to Synthesise 1H‐pyrazole via C–N and S–N Bond Cleavage

Abstract A novel and practical zinc‐catalysed synthesis of 1 H ‐pyrazole has been developed. The one‐pot protocol enables the cycloaddition of enaminone and tosylhydrazide via C−N and S−N bond breaking process, leading to diverse mono‐substituted pyrazole derivatives in high yields. Moreover, the easily accessible materials, broad substrate scope with excellent functional group tolerance, ease of isolation and open‐air conditions are the key features of the present method.