Highly Selective Epoxidation of Cycloaliphatic Alkenes with Aqueous Hydrogen Peroxide Catalyzed by [PO4{WO(O2)2}4]3−/Imidazole

Authors

  • Dr. Keigo Kamata,

    1. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220
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  • Kosei Sugahara,

    1. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220
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  • Dr. Ryo Ishimoto,

    1. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220
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  • Susumu Nojima,

    1. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220
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  • Motoya Okazaki,

    1. Fine Chemicals R&D Group, Chemicals Research Laboratory, Research & Development Division, JX Nippon Oil & Energy Corporation, 8 Chidoricho, Naka-ku, Yokohama 231-0815 (Japan)
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  • Dr. Takaya Matsumoto,

    1. Fine Chemicals R&D Group, Chemicals Research Laboratory, Research & Development Division, JX Nippon Oil & Energy Corporation, 8 Chidoricho, Naka-ku, Yokohama 231-0815 (Japan)
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  • Prof. Dr. Noritaka Mizuno

    Corresponding author
    1. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220
    • Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan), Fax: (+81) 3-5841-7220

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Abstract

In the presence of imidazole as an additive, a phosphorus-containing tetranuclear peroxotungstate, THA3[PO4{WO(O2)2}4] (I, THA=tetra-n-hexylammonium), could act as an efficient catalyst for epoxidation of cycloaliphatic alkenes with 30 % aqueous hydrogen peroxide (H2O2). Compound I showed higher catalytic activity and selectivity to epoxide than other tungstates. By using the I/imidazole system, various kinds of cycloaliphatic alkenes could be highly selectively converted into the acid-sensitive epoxides including industrially important diepoxides in high to excellent yields under the almost stoichiometric conditions. The 1H NMR spectroscopy showed that imidazole would work not only as a proton acceptor but also as a Lewis base to remarkably suppress the acid-catalyzed ring opening of epoxides.

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