Brønsted Acid Catalysis: Hydrogen Bonding versus Ion Pairing in Imine Activation

Authors

  • Matthias Fleischmann,

    1. Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany), Fax: (+49) 941-943-4617
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  • Diana Drettwan,

    1. Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany), Fax: (+49) 941-943-4617
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  • Dr. Erli Sugiono,

    1. Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen (Germany), Fax: (+49) 241-809-2665
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  • Prof. Dr. Magnus Rueping,

    Corresponding author
    1. Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen (Germany), Fax: (+49) 241-809-2665
    • Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen (Germany), Fax: (+49) 241-809-2665
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  • Prof. Dr. Ruth M. Gschwind

    Corresponding author
    1. Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany), Fax: (+49) 941-943-4617
    • Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany), Fax: (+49) 941-943-4617
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  • This research was supported by the DFG (SPP 1179).

Abstract

original image

Behind the scenes: NMR spectroscopy was used to distinguish hydrogen bonding and ion pairing in the activation of imines by a phosphate catalyst (see structures). Hydrogen-bond strength and the amount of the hydrogen-bonded species present are decisive for the catalytic reaction and can be manipulated by introducing substituents with different electronic properties. This insight should guide the development of more efficient catalytic systems.

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