Rhodium-Catalyzed ortho-Bromination of O-Phenyl Carbamates Accelerated by a Secondary Amide-Pendant Cyclopentadienyl Ligand

It has been established that a newly developed cyclopentadienyl rhodium(III) [(CpRhIII)-Rh-A] complex, bearing an acidic secondary amide moiety on the Cp ring, is able to catalyze the ortho-bromination of O-phenyl carbamates with N-bromosuccinimide (NBS) at room temperature. The presence of the acidic secondary amide moiety on the Cp-A ligand accelerates the bromination by the hydrogen bond between the acidic NH group of the Cp-A ligand and the carbonyl group of NBS.