Three-Component Synthesis Of 3,4-Disubstituted Pyrazoles Using Diazosulfone As A Diazomethane Surrogate

A three-component synthesis of 3-acyl-4-(het)arylpyrazoles employing aldehydes, Horner-Wadsworth-Emmons reagents, and -diazo--ketosulfone has been achieved. The reaction involves a domino HWE reaction/1,3-dipolar cycloaddition/desulfonylation process and generates the pyrazole derivatives in excellent yields. This three-component strategy provides a versatile platform to synthesize a range of 3,4-disubstituted pyrazoles employing diazoketosulfone as a diazomethane surrogate. The reaction exhibits high functional group tolerance and works under ambient conditions.