Remote steric effects of C2-symmetric planar-chiral terpyridine ligands on copper-catalyzed asymmetric cyclopropanation reactions

Nanako Mugishima, Nobuhiro Kanomata, Norihiko Akutsu, Hironobu Kubota

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    A series of enantioselective cyclopropanation reactions of substituted alkenes with diazoacetates was investigated in the presence of Cu(OTf)2 with C2-symmetric planar-chiral bridged 2,2′:6′,2″-terpyridines. Planar-chiral terpyridine-copper complexes exhibited moderate diastereomeric excesses with good enantioselectivities of cis-cyclopropane products in catalytic asymmetric cyclopropanation reactions of various styrene derivatives with ethyl diazoacetate. A remote steric effect was found to enhance enantioselectivity for the cyclopropanation induced by a sterically demanding substituent beyond the ansa-bridge of pyridinophane ligands on the other side of the reaction site as a relay of steric influences through flexible cyclophane bridges.

    Original languageEnglish
    Pages (from-to)1898-1903
    Number of pages6
    JournalTetrahedron Letters
    Volume56
    Issue number14
    DOIs
    Publication statusPublished - 2015 Apr 1

    Fingerprint

    Styrene
    Enantioselectivity
    Alkenes
    Copper
    Ligands
    Derivatives
    cyclopropane
    diazoacetic ester
    trifluoromethanesulfonic acid

    Keywords

    • Asymmetric cyclopropanation
    • Copper carbenoid
    • Planar chirality
    • Remote steric effect
    • Terpyridine

    ASJC Scopus subject areas

    • Biochemistry
    • Organic Chemistry
    • Drug Discovery

    Cite this

    Remote steric effects of C2-symmetric planar-chiral terpyridine ligands on copper-catalyzed asymmetric cyclopropanation reactions. / Mugishima, Nanako; Kanomata, Nobuhiro; Akutsu, Norihiko; Kubota, Hironobu.

    In: Tetrahedron Letters, Vol. 56, No. 14, 01.04.2015, p. 1898-1903.

    Research output: Contribution to journalArticle

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    AU - Mugishima, Nanako

    AU - Kanomata, Nobuhiro

    AU - Akutsu, Norihiko

    AU - Kubota, Hironobu

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    AB - A series of enantioselective cyclopropanation reactions of substituted alkenes with diazoacetates was investigated in the presence of Cu(OTf)2 with C2-symmetric planar-chiral bridged 2,2′:6′,2″-terpyridines. Planar-chiral terpyridine-copper complexes exhibited moderate diastereomeric excesses with good enantioselectivities of cis-cyclopropane products in catalytic asymmetric cyclopropanation reactions of various styrene derivatives with ethyl diazoacetate. A remote steric effect was found to enhance enantioselectivity for the cyclopropanation induced by a sterically demanding substituent beyond the ansa-bridge of pyridinophane ligands on the other side of the reaction site as a relay of steric influences through flexible cyclophane bridges.

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    KW - Copper carbenoid

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    KW - Remote steric effect

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