Gold-catalyzed benzannulation

Naoki Asao, Kenichiro Sato

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)

    Abstract

    Gold-catalyzed formal [4 + 2] benzannulation between enynal or enynone units, including ortho/alkynyl(oxo)benzenes, and 2π-systems, such as alkynes and carbonyl compounds (enol forms), produces aromatic ketones in good to high yields. By simply changing the catalyst from gold to copper-Brønsted acid system, decarbonylated aromatic compounds can be prepared in the reactions using alkynes as the 2π-system. An efficient synthetic approach to angucyclinone antibiotics, (+)-ochromycinone and (+)-rubiginone B2, is developed by applying the present benzannulation to an intramolecular version. The reaction proceeds most probably through the formation of the benzo [c]pyrylium ate complex via the intramolecular nucleophilic addition of the carbonyl oxygen atom to the alkyne part of enynal or enynone units, which is induced by carbophilic gold catalyst.

    Original languageEnglish
    Pages (from-to)897-904
    Number of pages8
    JournalYuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry
    Volume65
    Issue number9
    DOIs
    Publication statusPublished - 2007 Sep

    Keywords

    • (+)-ochromycinone
    • Benzannulation
    • Benzo cjpyrylium ate complex
    • Carbophilic Lewis acid
    • Copper catalyst
    • Gold catalyst

    ASJC Scopus subject areas

    • Organic Chemistry

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