Iron-Catalyzed Arene C–H Amidation Using Functionalized Hydroxyl Amines at Room Temperature

Herein, we report Fe(III)(TPP)Cl as an effective catalyst for promoting arene C–H amidation through intramolecular cyclization of N-tosyloxyarylcarbamate substrates. The reaction proceeds via nitrene (outer sphere pathway) C­(sp2)–H insertion to yield benzoxazolones under external-oxidant-free conditions at ambient temperature. The method is operationally simple and scalable with high-functional-group tolerance. Preliminary experimental and computational data indicates involvement of electrophilic aromatic substitution mechanism for this aryl C–H amidation transformation, distinct from operating mechanism reported previously in aryl C–H amination using azide-based substrates.