Cu-Catalyzed Synthesis of Symmetric Diarylamines from Organoboronic Acids Using NaNO₂ as the Amino Source

A copper-catalyzed novel synthesis of symmetric diarylamines was achieved from aryl boronic acids and NaNO2. This protocol employs aryl boronic acids as the commercially available arylation reagents and sodium nitrite (NaNO2) as the cheap, stable, and solid amino source. Under a simple ligand- and base-free copper catalytic system (CuCl as the sole catalyst), a wide range of symmetric diarylamines could be obtained in moderate to good yields. Notably, the use of Na15NO2 could produce 15N-labeled diarylamines, which would otherwise be difficult to prepare by the known methods.