Iron-Catalyzed Aerobic Oxidative Aromatic Coupling of Unprotected Primary Arylamines.

A ligand-free, iron-catalyzed aerobic oxidative coupling of unprotected primary arylamines is reported. Utilizing inexpensive FeCl3 and ambient air as the terminal oxidant, this protocol enables chemoselective ortho-ortho C(sp2)-C(sp2) bond formation while bypassing traditional N-protection requirements. The method accommodates regioselective homo- and cross-coupling of primary arylamines, alongside heterocoupling with phenolic substrates, providing a protection-free platform for constructing complex biaryls directly from primary anilines.