Rhodium(II)-Catalyzed Undirected and Selective C(sp2)–H Amination en Route to Benzoxazolones

Rhodium(II) can effectively promote the activation and cyclization of arylcarbamate substrates to yield benzoxazolones via an intramolecular nitrene C–H insertion reaction. Investigation of the substrate scope shows that the reaction undergoes selective aromatic C(sp2)—H amination over more labile o-C(sp3)—H bonds. Observation of inverse secondary KIE (PH/PD = 0.42 ± 0.03) indicates involvement of aromatic electrophilic substitution mechanism for this aryl C–H amidation transformation.