Enantioselective 5-endo-dig Carbocyclization of β-Ketoesters with Internal Alkynes Employing a Four-Component Catalyst System

Authors

  • Satoru Suzuki,

    1. Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan)
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  • Etsuko Tokunaga,

    1. Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan)
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  • Dhande Sudhakar Reddy,

    1. Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan)
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  • Takashi Matsumoto,

    1. Rigaku Corporation, 3-9-12 Mastubara-cho, Akishima Tokyo 196-8666 (Japan)
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  • Dr. Motoo Shiro,

    1. Rigaku Corporation, 3-9-12 Mastubara-cho, Akishima Tokyo 196-8666 (Japan)
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  • Prof. Norio Shibata

    Corresponding author
    1. Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan)
    • Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan)
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  • This study was financially supported in part by Grants-in-Aid for Scientific Research (21390030, 22106515, Project No. 2105: Organic Synthesis Based on Reaction Integration). We also thank TOSOH F-TECH INC., and the Asahi Glass Foundation for support in part. E.T. acknowledges Grants-in-Aid for Scientific Research for financial support (23915014).

Abstract

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It takes four: The title reaction was achieved for the first time by employing a four-component catalyst system, ZnII/Box-Ph/Yb(OTf)3/HFIP, to deliver the products in high yields and enantioselectivities. Fluorination of one of the products with Selectfluor provides a medicinally attractive allylic fluoride in good yield. Box-Ph=2,2′-isopropylidine bis(4-phenyl-2-oxazoline), HFIP=hexafluoroisopropyl alcohol.

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