General Au-Catalyzed Benzannulation Towards Naturally Occurring Carbazole Alkaloids from Methoxypropadiene

Authors

  • Wangqing Kong,

    1. Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (P.R. China), Fax: (+86) 21-62609305
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  • Chunling Fu,

    1. Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (P.R. China), Fax: (+86) 21-62609305
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  • Prof. Dr. Shengming Ma

    Corresponding author
    1. Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (P.R. China), Fax: (+86) 21-62609305
    • Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (P.R. China), Fax: (+86) 21-62609305
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Abstract

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Accessible alkaloids: Naturally occurring carbazole alkaloids, such as clauszoline-K, -L, -M, and -N, 3-formyl-7-hydroxycarbazole, and siamenol, were synthesized through a gold-catalyzed cyclization reaction of 1-(indol-2-yl)-2-methoxy-2,3-allenols, which are readily available from indolecarbaldehydes and methoxypropadiene (see scheme; R1=Me, carboxylic acid/ester, or aldehyde; R2=prenyl or H; R3=H or Me). The reaction demonstrates atom economy, high selectivity, and high yields, mostly with catalytic reactions.

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