Control of 6-Exo and 7-Endo Cyclizations of Alkynylamides using Platinum and Bismuth Catalysts

Authors

  • Dr. Anne-Lise Girard,

    1. Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569
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  • Taro Enomoto,

    1. Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569
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  • Shinsuke Yokouchi,

    1. Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569
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  • Dr. Chihiro Tsukano,

    1. Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569
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  • Prof. Dr. Yoshiji Takemoto

    Corresponding author
    1. Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569
    • Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan), Fax: (+81) 075-753-4569

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Abstract

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The rules of cyclization: Alkynylamides are regioselectively cycloisomerized into piperazin-2-one and 1,4-diazepan-2-one derivatives by using catalytic amounts of appropriate metal catalysts. A 6-exo-dig addition proceeds in the presence of Bi(OTf)3, while the 7-endo-dig addition occurs with PtCl2 for the same substrate. (see scheme; Ns=o-nitrobenzenesulfonyl, Ts=p-toluenesulfonyl, Cbz=benzyloxycarbonyl, DCE=dichloroethane)

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