Carbon–Carbon σ-Bond Transfer Hydrogenation with DMF Catalyzed by Cobalt Porphyrins

Abstract

Cobalt porphyrins were found to catalyze the transfer hydrogenation of the carbon–carbon σ bond of [2.2]paracyclophane (PCP) with the solvent DMF serving as the hydrogenating agent. Successful trapping experiments with benzene solvent and the kinetic isotope effect (4.9) suggested the presence of benzyl radical intermediates in undergoing hydrogen atom transfer from DMF as the rate-limiting step. The rate law was established by initial rate measurements to be rate = kobs[CoII(ttp)][PCP].