高等学校化学学报 ›› 1999, Vol. 20 ›› Issue (7): 1068.

• 论文 • 上一篇    下一篇

二溴卡宾与取代苯乙酮反应机理的研究

谷文祥1, 王洪星2, 还振威2   

  1. 1. 华南农业大学应用化学系, 广州 510642;
    2. 南开大学化学系, 天津 300071
  • 收稿日期:1998-10-30 出版日期:1999-07-24 发布日期:1999-07-24
  • 通讯作者: 王洪星
  • 作者简介:谷文祥,男,44岁,副教授.
  • 基金资助:

    国家自然科学基金(批准号:29372056)资助课题

Studies on the Mechanism of Reactions of Substituted Acetophenones with Dibromocarbene

GU Wen-Xiang1, WANG Hong-Xing2, HUAN Zhen-Wei 2   

  1. 1. Department of Applied Chemistry, South China Agriculture University, Guangzhou, 510642;
    2. Department of Chemistry, Nankai University , Tianjin, 300071
  • Received:1998-10-30 Online:1999-07-24 Published:1999-07-24

摘要: 研究了二溴卡宾与取代苯乙酮的反应机理.在取代苯乙酮与二溴卡宾的反应中,由于形成的羰基叶立德中间体的非平面构象,使得1,3-偶极加成难以发生,其主要反应途径为电环化和脱氧反应的竞争.当增大苯环上取代基的供电子能力时,原处于次要地位的脱氧反应的程度有所增强,但变化程度有限,故不能代替电环化成为主要反应.

关键词: 二溴卡宾, 取代苯乙酮, 脱氧反应, 羰基叶立德

Abstract: Mechanistic study on the reactions of dibromocarbene with para-substituted ace-tophenones suggests that the reactions proceed via the formation of a twisted carbonyl Ylide intermediate which causes two competitive pathways, i.e., (1) deoxygenation(in the form of losing CO and (2) electrocyclization. Although deoxygenation was observed not to be the major reaction path, it is clear that the extent of this reaction is increased substantively with respect to electron-donating substituents. This phenomena is rationalized based mainly on the electronic effect of substituents on each reaction path involved as well as the twisted con-firmation of Ylide intermediate.

Key words: Dibromocarbene, Acetophenone, Deoxygenation, Carbonyl Ylide

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