In Situ Generation of Nitrilimines from Aryldiazonium Salts and Diazo Esters: Synthesis of Fully Substituted Pyrazoles under Room Temperature.

A novel one-pot synthesis for fully substituted pyrazoles has been well developed via the in situ generation of nitrilimines from aryldiazonium salts and diazo esters and a subsequent cycloaddition with 1,3-dicarbonyl compounds. High yields, mild conditions, wide substrate scope, and operational simplicity are the significant advantages of this methodology.