English  |  正體中文  |  简体中文  |  全文筆數/總筆數 : 49074/83178 (59%)
造訪人次 : 6967600      線上人數 : 38
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library & TKU Library IR team.
搜尋範圍 查詢小技巧:
  • 您可在西文檢索詞彙前後加上"雙引號",以獲取較精準的檢索結果
  • 若欲以作者姓名搜尋,建議至進階搜尋限定作者欄位,可獲得較完整資料
  • 進階搜尋
    請使用永久網址來引用或連結此文件: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/19517


    題名: New Method for the Synthesis of Polyether-Bridged Azulenes: Reactions of Conjugated Ketocarbenes Generated from the Corresponding Azulenoquinone Diazides
    作者: Lin, Yun-shan;Jiang, Shuan-Ya;Huang, Tian-Chyuan;Lin, Shih-Jue;Chow, Yuan L.
    貢獻者: 淡江大學化學學系
    日期: 1998-04-29
    上傳時間: 2009-11-04 16:52:11 (UTC+8)
    出版者: Washington: American Chemical Society (ACS)
    摘要: The diazide of 2,4-azulenoquinone carrying 1,3-cyano and carbomethoxy substituents was synthesized and photolyzed in cyclic ethers (THF, dioxane, and tetrahydropyran) to give good yields of 2,4-polyether-bridged azulenes. The shapes of some azulene polyethers were examined by X-ray structural determination to show the cavity size ranging from 6.4 to 4.1 Å (long-short diameters) to 7.36-6.6 Å encircled by an azulene and polyether arc. In analogy to 2,5-cyclohexadien-4- onylidenes, photogenerated conjugated azulenone carbenes were assumed to have energetically closely spaced triplet and singlet ground states that can interconvert readily and react from one of these states under ambient conditions. The spanning of a polyether bridge is initiated by the electrophilic attack of a singlet state on the oxygen of solvent ethers, followed by one or two propagation steps and a ring closure by phenolate attack. The 1,3-dicarbomethoxy group could exert steric effects to hinder the approach of the ether oxygen and control the polyether spanning processes and ring size; this caused a triplet state reaction to supersede the overall reaction. While radical and insertion reactions are common for ketocarbene reactions, the present description adduces a well manifested electrophilic reaction of the allied transients.
    關聯: Journal of Organic Chemistry 63(10), pp.3364-3370
    DOI: 10.1021/jo971494u
    顯示於類別:[化學學系暨研究所] 期刊論文

    文件中的檔案:

    檔案 描述 大小格式瀏覽次數
    0022-3263_63(10)p3364-3370.pdf175KbAdobe PDF250檢視/開啟

    在機構典藏中所有的資料項目都受到原著作權保護.

    TAIR相關文章

    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library & TKU Library IR teams. Copyright ©   - 回饋