Palladium Catalytic Species Containing Chiral Phosphites: Towards a Discrimination between Molecular and Colloidal Catalysts

Authors

  • Isabelle Favier,

    1. Departament de Química Inorgànica, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain
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  • Montserrat Gómez,

    1. Departament de Química Inorgànica, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain
    2. Laboratoire Hétérochimie Fondamentale et Appliquée, UMR CNRS 5069, 118, route de Narbonne, 31062 Toulouse cedex 9, France, Fax: (+33)-5-6155-8204
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  • Guillermo Muller,

    1. Departament de Química Inorgànica, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain
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  • M. Rosa Axet,

    1. Departament de Química Física i Química Inorgànica i Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel⋅lí Domingo, s/n, 43007 Tarragona, Spain
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  • Sergio Castillón,

    1. Departament de Química Física i Química Inorgànica i Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel⋅lí Domingo, s/n, 43007 Tarragona, Spain
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  • Carmen Claver,

    1. Departament de Química Física i Química Inorgànica i Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel⋅lí Domingo, s/n, 43007 Tarragona, Spain
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  • Susanna Jansat,

    1. Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205, route de Narbonne, 31077 Toulouse cedex 04, France
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  • Bruno Chaudret,

    1. Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205, route de Narbonne, 31077 Toulouse cedex 04, France
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  • Karine Philippot

    1. Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205, route de Narbonne, 31077 Toulouse cedex 04, France
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Abstract

Palladium nanoparticles (Pd1Pd3) stabilized by chiral diphosphite ligands (13), were synthesized and tested as catalysts for the allylic alkylation reaction, using different substrates (rac-I, rac-III and rac-V). Carbohydrate ligands (1 and 2), only differing in the C-3 configuration, led to a remarkable difference in stability of the corresponding nanoparticles: while Pd1 is a robust catalyst, Pd2 decomposes into molecular species. In addition, the high enantioselective systems, Pd1 and Pd3, are only active for a substrate containing phenyl groups. Concerning the catalytic behaviour of the corresponding molecular systems, palladium complexes coordinated to ligands 1 or 3, gave excellent asymmetric inductions, but an analogous catalyst accommodating ligand 2, was not found selective.

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