Benzylic Oxidation Catalyzed by Cobalt(II)-Terpyridine Coordination Polymers

Direct benzylic C-H oxidation for the synthesis of aromatic ketones was developed.Employing cobalt(II)-terpyridine coordination polymers as catalyst, tert-butyl hydroperoxide (TBHP) as oxidant and Na2CO3 as activator, 19 aromatic ketones were prepared with good to excellent yields (78%～99%) in water.The reaction showed a broad range of substrates with good functional group tolerance and chemical selectivity.By control experiments, a trapping experiment using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and detection of intermediates during reaction, a reasonable radical mechanism for this type of reaction was also demonstrated.