Enantioselective Synthesis of Spirocyclic Benzopyranones by Rhodium-Catalyzed Intermolecular [4+2] Annulation

Authors

  • Daiki Hojo,

    1. Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan), Fax: (+81) 42-388-7037
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  • Keiichi Noguchi Prof. Dr.,

    1. Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)
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  • Masao Hirano Dr.,

    1. Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan), Fax: (+81) 42-388-7037
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  • Ken Tanaka Prof. Dr.

    1. Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan), Fax: (+81) 42-388-7037
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  • This work was partly supported by a Grant-in-Aid for Scientific Research (No. 19028015) from MEXT Japan and the Kato Memorial Foundation. We thank Solvias AG for the gift of chiral ferrocenyl bisphosphine ligands under their University Ligand Kit program. We also thank Y. Hagiwara for his preliminary experiments.

Abstract

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Verknüpft unter Cyclisierung: Ein kationischer Rhodium(I)-Komplex mit dem Liganden (R,R)-Walphos katalysiert bei Raumtemperatur die enantioselektive [4+2]-Anellierung von 2-Alkinylbenzaldehyden mit elektronenarmen cyclischen Carbonylverbindungen (siehe Schema, R3=3,5-(F3C)2C6H3; X=C,N). Enantiomerenangereicherte spirocyclische Benzopyranone und Isatinderivate werden mit hohen Ausbeuten (bis 97 %) und Enantioselektivitäten (bis >99 %) erhalten.

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