Base-catalyzed cascade [3 + 2] spiroannulation/aromatization of in situ generated tosyldiazomethane (TsDAM) with (Z)-aurones: An efficient access to polysubstituted pyrazole derivatives

An efficient metal-free approach to access in situ generated tosyldiazomethane (TsDAM) and (Z)-aurones containing pyrazoles under mild conditions has been developed. This methodology involves 1,3-dipolar cycloaddition in an aqueous system, followed by an aromatization with a CO bond cleavage in an acidic separation environment. We observed good yields under mild conditions, along with synthetic versatility and high functional group compatibility.