Enantioselective Hydrogenations on Platinum Colloids

Authors

  • Prof. Dr. Helmut Bönnemann,

    Corresponding author
    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr (Germany) Fax: Int. code +(208)3062983
    • Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr (Germany) Fax: Int. code +(208)3062983
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  • Dipl.-Chem. Gerhard A. Braun

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr (Germany) Fax: Int. code +(208)3062983
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  • This work is part of the planned thesis of G. Braun, RWTH Aachen. It was supported by the Bundesministerium für Bildung, Forschung, Technologie, und Wissenschaft, Bonn (FKZ 03 D 00007 A2), and the Funds der chemischen Industrie, Frankfurt. We thank Dr. Helmut Cölfen, Max-Planck-Institut für Kolloid- und Grenzflächenforschung/Teltow-Seehof, for the studies employing the analytical ultracentrifuge.

Abstract

The chemical reduction of aqueous solutions of platinum salts in the presence of the alkaloid dihydrocinchonidine yields chirally coated platinum colloids. The particle sizes can be varied in a controlled fashion from 1.5 to 4 nm by changing the alkaloid concentration. These chirally coated platinum colloids function in quasi-homogenous phases as enantioselective hydrogenation catalysts for ethylpyruvate (76% ee), and no structure sensitivity was observed.

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