Catalytic Phenol Hydroxylation with Dioxygen: Extension of the Tyrosinase Mechanism beyond the Protein Matrix

Authors


  • A.H., S.B., A.G., M.R., and S.H.-P. thank the Deutsche Forschungsgemeinschaft (FOR 1405) for financial support. S.H.-P. gratefully acknowledges the Fonds der Chemischen Industrie for a Liebig fellowship, the Bundesministerium für Bildung und Forschung initiative MoSGrid (01IG09006) for computational support, and Prof. Dr. K. Jurkschat for valuable advice. I.I.-B. and O.T. gratefully acknowledge support through the “Solar Technologies Go Hybrid” initiative of the State of Bavaria. Financial support was provided by the U.S. National Institutes of Health (NIH; GM50730) for T.D.P.S. and the William R. and Sara Hart Kimball Stanford Graduate Fellowship for C.C. E.C.W. thanks the CSU Chico College of Natural Sciences for financial support and release time to support this work. Portions of this research were carried out at the Stanford Synchrotron Radiation Laboratory, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

Abstract

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A new catalyst (see structure) hydroxylates phenols with O2 via a stable side-on peroxide complex, which is similar to the active site of tyrosinase in terms of the ligand environment and its spectroscopic properties. The catalytic oxidation of phenols to quinones proceeds at room temperature in the presence of NEt3 and even non-native substrates can be oxidized catalytically. The reaction mechanism is analogous to that of the enzyme-catalyzed reaction.

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