title: β-Hydride Elimination at Low-Coordinate Gold(III) Centers.
abstract: This Article reports the first comprehensive study of β-hydride elimination at gold(III). The stability/fate of gold(III) alkyl species have been investigated experimentally and computationally. A series of well-defined cationic cyclometalated gold(III) alkyl complexes [(P,C)gold(III)(R)][NTf2] [(P,C) = 8-diisopropylphosphino-naphthyl; R = Me, nPr, nBu] have been synthesized and spectroscopically characterized. While the cationic gold(III) methyl derivative 3c is stable for days at room temperature, the gold(III) n-propyl and n-butyl complexes 3a,b readily undergo β-hydride elimination at low temperature to generate propylene and 2-butenes, respectively. The formation of internal olefins from the gold(III) n-butyl complex 3b shows that olefin isomerization takes place after β-hydride elimination. Computational studies indicate that this isomerization proceeds through a chain-walking mechanism involving a highly reactive gold(III) hydride intermediate and a sequence of β-hydride elimination/reinsertion into the Au-H bond. The reaction of the cationic gold(III) methyl complex 3c with ethylene was also explored. According to (1)H and (13)C NMR spectroscopy, a mixture of propylene, 1-butene, and 2-butenes is formed. DFT calculations provide detailed mechanistic insights and support the occurrence of migratory insertion of ethylene, β-hydride elimination, and olefin exchange at gold(III).
authors.affiliation: UPS, Laboratoire Hétérochimie Fondamentale Appliquée, Université de Toulouse and CNRS, LHFA UMR 5069 , 118 route de Narbonne, Toulouse F-31062, France.
authors.forename: Feriel
authors.initials: F
authors.lastname: Rekhroukh
authors.affiliation: Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, Université de Pau et des Pays de l'Adour and CNRS, IPREM UMR 5254 , Hélioparc, 2 Avenue du Président Angot, Pau 64053 Cedex 09, France.|Departamento de Química Física, Facultade de Química, Universidade de Vigo , Lagoas-Marcosende s/n, 36310 Vigo, Galicia, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Estevez
authors.affiliation: Institut de Chimie de Toulouse (FR 2599) , 118 Route de Narbonne, Toulouse 31062 Cedex 09, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Mallet-Ladeira
authors.affiliation: Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, Université de Pau et des Pays de l'Adour and CNRS, IPREM UMR 5254 , Hélioparc, 2 Avenue du Président Angot, Pau 64053 Cedex 09, France.
authors.forename: Karinne
authors.initials: K
authors.lastname: Miqueu
authors.affiliation: UPS, Laboratoire Hétérochimie Fondamentale Appliquée, Université de Toulouse and CNRS, LHFA UMR 5069 , 118 route de Narbonne, Toulouse F-31062, France.
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Amgoune
authors.affiliation: UPS, Laboratoire Hétérochimie Fondamentale Appliquée, Université de Toulouse and CNRS, LHFA UMR 5069 , 118 route de Narbonne, Toulouse F-31062, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Bourissou