Visible-Light-Mediated Nickel(II)-Catalyzed C–N Cross-Coupling in Water: Green and Regioselective Access for the Synthesis of Pyrazole-Containing Compounds

A regioselective green approach for the nickel­(II)-catalyzed C–N cross-coupling between arylamines and pyrazoles through a photoredox process is reported. Moderate to good yield was observed for this reaction, performed in water under air at room temperature. This strategy provides a powerful tool for the green synthesis of pyrazole-containing bioactive molecules. In addition, a single-electron-transfer mechanism is proposed in this report.