Highly Recyclable Self-Supported Chiral Catalysts for the Enantioselective α-Hydrazination of β-Ketoesters

Authors

  • Maria Torres,

    1. Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France), Fax: (+33) 388 107 246
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  • Dr. Aline Maisse-François,

    1. Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France), Fax: (+33) 388 107 246
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  • Dr. Stéphane Bellemin-Laponnaz

    Corresponding author
    1. Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France), Fax: (+33) 388 107 246
    • Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France), Fax: (+33) 388 107 246
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Abstract

Multitopic chiral copper complexes based on bis(oxazoline) have been applied in the enantioselective α-hydrazination of β-ketoesters. High yields and excellent enantioselectivities were obtained. Furthermore, the catalytic systems have been recovered in up to ten cycles without loss of activity or enantioselectivity. The formation of coordination polymers [polytopic ligand–Cu]n has been confirmed by UV/Vis titrations. Significant metal leaching was observed on increasing the topicity of the ligand. The nature of the catalyst was studied by nonlinear effect experiments.

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