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Copper‐catalyzed Monooxygenation of Phenols: Evidence for a Mononuclear Reaction Mechanism

Rebecca SchneiderTobias Adrian EngesserChristian NätherIngo KrossingFelix Tuczek

出版	Universität, 2022
URL	http://books.google.com.hk/books?id=yTeazwEACAAJ&hl=&source=gbs_api

註釋Abstract: The CuI salts [Cu(CH3CN)4]PF and [Cu(oDFB)2]PF with the very weakly coordinating anion Al(OC(CF3)3)4− (PF) as well as [Cu(NEt3)2]PF comprising the unique, linear bis-triethylamine complex [Cu(NEt3)2]+ were synthesized and examined as catalysts for the conversion of monophenols to o-quinones. The activities of these CuI salts towards monooxygenation of 2,4-di-tert-butylphenol (DTBP-H) were compared to those of [Cu(CH3CN)4]X salts with "classic" anions (BF4−, OTf−, PF6−), revealing an anion effect on the activity of the catalyst and a ligand effect on the reaction rate. The reaction is drastically accelerated by employing CuII-semiquinone complexes as catalysts, indicating that formation of a CuII complex precedes the actual catalytic cycle. This result and other experimental observations show that with these systems the oxygenation of monophenols does not follow a dinuclear, but a mononuclear pathway analogous to that of topaquinone cofactor biosynthesis in amine oxidase