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(sp(2))-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.