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    Asymmetric synthesis of alpha,alpha-disubstituted alpha-amino acids by diastereoselective alkylation of camphor-based tricyclic iminolactone.

    Authors
    Xu PF, Li S, Lu TJ, et al. 
    Source
    J Org Chem 2006 Jun 9; 71(12) :4364-73.
    Abstract

    A novel and convenient route for the preparation of chiral tricyclic iminolactones 9 and 10 from camphorquinone has been developed. Alkylation of iminolactones 9 and 10 provided iminolactones 16 and 17 in high yields which were, in turn, alkylated again to afford the alpha,alpha-disubstituted products in good yields (70-90%) and excellent diastereoselectivities (>98%). Hydrolysis of the alkylated iminolactones furnished the desired alpha,alpha-disubstituted alpha-amino acids in good yields and high enantiomeric excesses with good recovery yields of the chiral auxiliary 12 and 13. The extremely high endo-face selectivity for alkylation is discussed using semiempirical (MOPAC 93) calculations.

    Mesh
    Alkylation
    Amino Acids
    Camphor
    Heterocyclic Compounds, 3-Ring
    Imines
    Lactones
    Models, Molecular
    Stereoisomerism
    Language

    eng

    Pub Type(s)
    Journal Article Research Support, Non-U.S. Gov't
    PubMed ID

    16749763

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