title: Origin of the Oxygen Atom in C-H Bond Oxidations Catalyzed by a Water-Soluble Metalloporphyrin.
abstract: The monopersulfate oxidation of 4-isopropylbenzoic acid performed in H(2)(18)O and catalyzed by a water-soluble metalloporphyrin indicated that half of the oxygen atoms incorporated in 4-(1-hydroxy-1-methylethyl)benzoic acid, the primary hydroxylation product, came from water. A redox tautomerism of the active high-valent hydroxo-metal-oxo porphyrin intermediate coupled with an oxygen rebound mechanism explained this result. Under similar conditions, ketoprofen was directly oxidized to 3-benzoylacetophenone, via at least two different reaction pathways. Trapping of radical intermediates by molecular oxygen competed with the oxygen rebound mechanism.
authors.affiliation: Chemistry Department, University of Guelph, Ontario N1G 2W1, Canada, and Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France.
authors.forename: Robert J.
authors.initials: RJ
authors.lastname: Balahura
authors.forename: Alexander
authors.initials: A
authors.lastname: Sorokin
authors.forename: Jean
authors.initials: J
authors.lastname: Bernadou
authors.forename: Bernard
authors.initials: B
authors.lastname: Meunier