Aromatic and Benzylic C−H Bond Activation in the System Bis(dicarbonylrhodium(I))- porphyrinate−Hydrocarbon Solvent

Metalation of C6H6 has been known for a long time as a side reaction occurring in refluxing benzene solutions of Rh2(CO)4(TPP) (TTP = tetraphenylporphyrin). Rather than representing the intrinsic reactivity of this complex, such hydrocarbon activation proceeds via RhII(por) and RhIII(por) derivatives resulting from oxidation of Rh2(CO)4(TPP) with adventitious H2O and/or O2. This reaction can be extended to other aromatic substrates and represents an efficient synthetic route to certain organometallic RhIII(TPP) derivatives.