K2CO3-Promoted Consecutive Carbon-Hydrogen and Carbon-Carbon Bond Activation of Cycloheptane with Rhodium(III) Porphyrin Complexes: Formation of Rhodium Porphyrin Cycloheptyl and Benzyl

K2CO3-promoted carbon hydrogen and carbon-carbon bond activations of cycloheptane are achieved with rhodium(III) tetrakis(4-tolyl)porphyrin chloride (Rh-(ttp)CI) at 120 degrees C to give Rh(ttp) cycloheptyl and benzyl complexes. On the basis of mechanistic studies, Rh(ttp)CI first reacts by ligand substitution to give Rh(ttp)OH, which then undergoes reductive elimination to give Rh-2(II)(ttp)(2). The metalloradical Rh-II(ttp), formed via dissociation of Rh-2(II),(ttp)2, activates the CH bond of cycloheptane to form Rh(ttp)(cycloheptyl) and Rh(ttp)H. Rh(ttp)(cycloheptyl) slowly yields Rh(ttp)(cycloheptatrieneyl) by successive beta-hydride elimination to olefins and Rh(ttp)H. K2CO3 promoted the dehydrogenation of Rh(ttp)H to give Rh-2(II)(ttp)(2) and H-2. Both Rh(ttp)H and Rh-2(II)(ttp)(2) activate the cycloheptatriene to give Rh(ttp)(cycloheptatrienyl), which further undergoes a Rh-II(ttp)-catalyzed skeletal rearrangement to form Rh(ttp)Bn with rate enhancement much faster than that of the analogous organic isomerization of cycloheptatriene to toluene.