Synthesis of enantiopure phthalides including 3-butylphthalide, a fragrance component of celery oil, and determination of their absolute configurations

Masashi Kosaka, Satoshi Sekiguchi, Junpei Naito, Makoto Uemura, Shunsuke Kuwahara, Masataka Watanabe, Nobuyuki Harada, Kunio Hiroi

    Research output: Contribution to journalArticle

    50 Citations (Scopus)

    Abstract

    Enantiopure phthalides 2 and 5-8 were synthesized via enantioresolution of the corresponding alcohols with a chiral auxiliary of camphorsultam dichlorophthalic acid, (1S,2R,4R)-(-)-CSDP acid 3, followed by solvolysis with KOH in MeOH and the catalytic oxidation of chiral glycols with iridium complex 28. The absolute configurations of phthalides 2 and 5-8 were determined by applying the 1H-NMR anisotropy method of MαNP acid (4), 2-methoxy-2-(1-naphthyl)propionic acid, to the chiral synthetic precursory alcohols. In the case of 3-phenylphthalide (R)-(-)-7, the absolute configuration determined by the 1H-NMR anisotropy method using MαNP acid 4 agreed with that by the X-ray crystallographic method. By applying these methods, 3-butylphthalide (S)-(-)-2, a fragrance component of essential oil of celery, has been synthesized in an enantiopure form, and its absolute configuration was unambiguously determined.

    Original languageEnglish
    Pages (from-to)218-232
    Number of pages15
    JournalChirality
    Volume17
    Issue number4
    DOIs
    Publication statusPublished - 2005 May 11

    Keywords

    • (1S,2R,4R)-(-)-CSDP acid
    • 2-methoxy-2-(1-naphthyl)propionic acid
    • Absolute configuration
    • Camphorsultam dichlorophthalic acid
    • Chiral H-NMR anisotropy reagent
    • Chiral auxiliary
    • Chiral phthalides
    • Enantioresolution
    • MαNP acid

    ASJC Scopus subject areas

    • Analytical Chemistry
    • Catalysis
    • Pharmacology
    • Drug Discovery
    • Spectroscopy
    • Organic Chemistry

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  • Cite this

    Kosaka, M., Sekiguchi, S., Naito, J., Uemura, M., Kuwahara, S., Watanabe, M., Harada, N., & Hiroi, K. (2005). Synthesis of enantiopure phthalides including 3-butylphthalide, a fragrance component of celery oil, and determination of their absolute configurations. Chirality, 17(4), 218-232. https://doi.org/10.1002/chir.20156