Cp*CoIII-Catalyzed C2-Selective Addition of Indoles to Imines

Authors

  • Tatsuhiko Yoshino,

    1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
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  • Hideya Ikemoto,

    1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
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  • Dr. Shigeki Matsunaga,

    Corresponding author
    1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
    2. ACT-C Japan Science and Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
    • Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
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  • Prof. Dr. Motomu Kanai

    Corresponding author
    1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
    2. ERATO, Kanai Life Science Catalysis Project, Japan Science and Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
    • Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-5206
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  • Cp*=1,2,3,4,5-pentamethylcyclopentadienyl; Cp*CoIII=a CoIII complex with one Cp* ligand and other coordinating ligand(s), such as C6H6, a base (OAc), or a substrate (imine or a pyrimidine unit in indoles).

Abstract

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Overriding innate reactivity: The utility of a CoIII catalyst to promote the C2-selective addition of indoles to imines was demonstrated. The CoIII catalyst completely changed the regioselectivity in comparison with simple Lewis acid catalyzed Friedel–Crafts C3-selective addition. High turnover number (TON) of the catalyst, up to 1.8×102 (with s/c=200; see scheme; s/c is the substrate/catalyst ratio), was achieved.

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