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.