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Enantioselective Amine-Catalyzed [4+2] Annulations of Allenoates and Oxo-dienes: An Asymmetric Synthesis of Dihydropyrans

Authors

  • Xiaojun Wang,

    1. Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (China), Fax: (+86) 21-6425-3881
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  • Tong Fang,

    1. Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (China), Fax: (+86) 21-6425-3881
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  • Dr. Xiaofeng Tong

    Corresponding author
    1. Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (China), Fax: (+86) 21-6425-3881
    • Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237 (China), Fax: (+86) 21-6425-3881
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  • Support of this work by the NSFC (No. 21002025) and the Shanghai Municipal Committee of Science and Technology (No. 09ZR1408500) is greatly appreciated. This work is also supported by the Fundamental Research Funds for the Central Universities. We thank Dr. Kun Liu (SIOC) for theoretical calculations. Special gratitude goes to Professors Xingyi Wang and Limin Wang for their long-term support.

Abstract

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Biologically significant polysubstituted dihydropyrans have been prepared in high to excellent yields and enantioselectivities (see scheme). The interaction between functional groups in the zwitterionic intermediate, which is generated by addition of the amine catalyst to the allenoate substrate, is thought to play a crucial role in the stereochemical outcome. Bn=benzyl, DMAP=4-dimethylaminopyridine.

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