Azirine-enabled regioselective synthesis of N -alkyl pyrazoles and indole–pyrazole conjugates via Cu-catalysed N–N bond formation

-alkyl pyrazoles in good to excellent yields under mild, operationally simple, and ambient conditions. The strategy efficiently accommodates aliphatic amines and α-amino esters, delivering aliphatic pyrazoles with comparable efficiency. Moreover, the synthesis of novel classes of indole-pyrazole conjugates underscores the versatility of this approach. This protocol avoids hazardous reagents and harsh conditions, offering a practical alternative to conventional pyrazole synthesis. The broad substrate scope and synthetic utility of this method, exemplified by the rapid access to drug-like scaffolds, highlight its potential application in medicinal chemistry.