Asymmetric ortho-lithiation of 1,n-dioxa[n]paracyclophane derivatives for the generation of planar chirality

Kazumasa Kanda, Risa Hamanaka, Kohei Endo, Takanori Shibata

    Research output: Contribution to journalArticle

    20 Citations (Scopus)

    Abstract

    The asymmetric induction of planar chirality in 1,n-dioxa[n]paracyclophane derivatives via asymmetric ortho-lithiation is described. Enantioselective ortho-lithiation of unflippable 1,n-dioxa[n]paracyclophanes (n≤11) using sec-BuLi-(-)-sparteine at -78 °C and subsequent treatment with electrophiles gave the corresponding planar-chiral monosubstituted paracyclophanes with excellent ee. Further lithiation of these compounds and treatment with electrophiles gave planar-chiral paracyclophanes with two different substituents. Dilithiation of unflippable 1,n-dioxa[n]paracyclophanes gave the corresponding C 2-symmetrical disubstituted products with almost perfect ee. In the case of flippable 1,n-dioxa[n]paracyclophanes (n≥12), a stepwise reaction was required for the highly enantioselective formation of disubstituted products.

    Original languageEnglish
    Pages (from-to)1407-1416
    Number of pages10
    JournalTetrahedron
    Volume68
    Issue number5
    DOIs
    Publication statusPublished - 2012 Feb 4

    Fingerprint

    Sparteine
    Chirality
    Derivatives

    Keywords

    • Enantioselective
    • ortho-Lithiation
    • Paracyclophane
    • Planar chirality

    ASJC Scopus subject areas

    • Biochemistry
    • Organic Chemistry
    • Drug Discovery

    Cite this

    Asymmetric ortho-lithiation of 1,n-dioxa[n]paracyclophane derivatives for the generation of planar chirality. / Kanda, Kazumasa; Hamanaka, Risa; Endo, Kohei; Shibata, Takanori.

    In: Tetrahedron, Vol. 68, No. 5, 04.02.2012, p. 1407-1416.

    Research output: Contribution to journalArticle

    Kanda, Kazumasa ; Hamanaka, Risa ; Endo, Kohei ; Shibata, Takanori. / Asymmetric ortho-lithiation of 1,n-dioxa[n]paracyclophane derivatives for the generation of planar chirality. In: Tetrahedron. 2012 ; Vol. 68, No. 5. pp. 1407-1416.
    @article{7b189b91e34d436e90e6166e2641f3f1,
    title = "Asymmetric ortho-lithiation of 1,n-dioxa[n]paracyclophane derivatives for the generation of planar chirality",
    abstract = "The asymmetric induction of planar chirality in 1,n-dioxa[n]paracyclophane derivatives via asymmetric ortho-lithiation is described. Enantioselective ortho-lithiation of unflippable 1,n-dioxa[n]paracyclophanes (n≤11) using sec-BuLi-(-)-sparteine at -78 °C and subsequent treatment with electrophiles gave the corresponding planar-chiral monosubstituted paracyclophanes with excellent ee. Further lithiation of these compounds and treatment with electrophiles gave planar-chiral paracyclophanes with two different substituents. Dilithiation of unflippable 1,n-dioxa[n]paracyclophanes gave the corresponding C 2-symmetrical disubstituted products with almost perfect ee. In the case of flippable 1,n-dioxa[n]paracyclophanes (n≥12), a stepwise reaction was required for the highly enantioselective formation of disubstituted products.",
    keywords = "Enantioselective, ortho-Lithiation, Paracyclophane, Planar chirality",
    author = "Kazumasa Kanda and Risa Hamanaka and Kohei Endo and Takanori Shibata",
    year = "2012",
    month = "2",
    day = "4",
    doi = "10.1016/j.tet.2011.12.031",
    language = "English",
    volume = "68",
    pages = "1407--1416",
    journal = "Tetrahedron",
    issn = "0040-4020",
    publisher = "Elsevier Limited",
    number = "5",

    }

    TY - JOUR

    T1 - Asymmetric ortho-lithiation of 1,n-dioxa[n]paracyclophane derivatives for the generation of planar chirality

    AU - Kanda, Kazumasa

    AU - Hamanaka, Risa

    AU - Endo, Kohei

    AU - Shibata, Takanori

    PY - 2012/2/4

    Y1 - 2012/2/4

    N2 - The asymmetric induction of planar chirality in 1,n-dioxa[n]paracyclophane derivatives via asymmetric ortho-lithiation is described. Enantioselective ortho-lithiation of unflippable 1,n-dioxa[n]paracyclophanes (n≤11) using sec-BuLi-(-)-sparteine at -78 °C and subsequent treatment with electrophiles gave the corresponding planar-chiral monosubstituted paracyclophanes with excellent ee. Further lithiation of these compounds and treatment with electrophiles gave planar-chiral paracyclophanes with two different substituents. Dilithiation of unflippable 1,n-dioxa[n]paracyclophanes gave the corresponding C 2-symmetrical disubstituted products with almost perfect ee. In the case of flippable 1,n-dioxa[n]paracyclophanes (n≥12), a stepwise reaction was required for the highly enantioselective formation of disubstituted products.

    AB - The asymmetric induction of planar chirality in 1,n-dioxa[n]paracyclophane derivatives via asymmetric ortho-lithiation is described. Enantioselective ortho-lithiation of unflippable 1,n-dioxa[n]paracyclophanes (n≤11) using sec-BuLi-(-)-sparteine at -78 °C and subsequent treatment with electrophiles gave the corresponding planar-chiral monosubstituted paracyclophanes with excellent ee. Further lithiation of these compounds and treatment with electrophiles gave planar-chiral paracyclophanes with two different substituents. Dilithiation of unflippable 1,n-dioxa[n]paracyclophanes gave the corresponding C 2-symmetrical disubstituted products with almost perfect ee. In the case of flippable 1,n-dioxa[n]paracyclophanes (n≥12), a stepwise reaction was required for the highly enantioselective formation of disubstituted products.

    KW - Enantioselective

    KW - ortho-Lithiation

    KW - Paracyclophane

    KW - Planar chirality

    UR - http://www.scopus.com/inward/record.url?scp=84855601605&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84855601605&partnerID=8YFLogxK

    U2 - 10.1016/j.tet.2011.12.031

    DO - 10.1016/j.tet.2011.12.031

    M3 - Article

    AN - SCOPUS:84855601605

    VL - 68

    SP - 1407

    EP - 1416

    JO - Tetrahedron

    JF - Tetrahedron

    SN - 0040-4020

    IS - 5

    ER -