Regioselective C-H oxidation of aliphatic molecules with synthetic catalysts is challenging. Here, we incorporated substraterecognition sites into a ruthenium porphyrin-heteroaromatic N-oxide catalyst system in order to characterize the regioselectivity for oxidation of alkanes. Specifically, we synthesized ruthenium porphyrin bearing two 6-acylaminopyridyl-2-amide moieties at anti sites and a series of substrates consisting of a polymethylene chain terminated by two quinazoline-2,4-dione moieties, each of which should form three hydrogen bonds with the catalyst. Oxidation proceeded at the central position of the polymethylene chain and selectively afforded the corresponding ketone (7-oxo) as the major product. The reaction rate was greater than that of a catalyst without recognition sites. The enhanced rate and high regioselectivity are considered to be a result of the proximity between the active intermediate and the reaction site owing to molecular recognition.
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