title: [Phenoxenium ions: generations and reactions].
abstract: The acid-catalyzed reaction of N-acyl- and N-sulfonylhydroxylamines with benzene proceeded smoothly to give C-C products; 2- and 4-hydroxybiphenyls. The reaction and the thermolysis of N-aryloxypyridinium salts involve common intermediates. The results of product analysis, the orientation of the reaction, effects of substituents on the nitrogen atom and on the phenyl ring suggested a mechanism involving a phenoxenium ion. The positive charge of the phenoxenium ion localized not on the oxygen atom but on the ortho and para carbons of the benzene ring. C-O product: diphenylethers are formed when the heterolysis of the N-O bonds is slow and the aromatic solvent has high nucleophilicity, suggesting an SN2-like reaction on the oxygen atom. The phenoxenium ions are also concerned with a rearrangement of O-arylhydroxylamine to 2-aminophenol. An ion-molecule pair involving phenoxenium ion and ammonia as an intermediate of the intramolecular ortho rearrangement.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.forename: K
authors.initials: K
authors.lastname: Shudo
mesh_terms: D002384:Catalysis; D006898:Hydroxylamines; D010636:Phenols / Q000737:chemistry*
chemical_list: D006898:Hydroxylamines; D010636:Phenols; C012484:phenylhydroxylamine; C042329:phenoxy radical