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研究论文

苯并醌与炔烃的形式[6+2-1]环加成反应的机理研究

张谦玮a, 孔令荃a, 陈自立b, 余志祥a,*   

  1. a北京大学化学与分子工程学院 北京分子科学国家研究中心 生物有机与分子工程教育部重点实验室 北京 100871;
    b中国人民大学化学系 北京 100872
  • 收稿日期:2026-05-25 修回日期:2026-07-27
  • 基金资助:
    本研究工作得到国家自然科学基金(No. 22361142835)、北京大学高性能计算校级公共平台支持.

Mechanistic Study of the Formal [6+2-1] Cycloaddition of Benzoquinones and Alkynes to Tropones

Qianwei Zhanga, Ling-Quan Konga, Zili Chenb, Zhi-Xiang Yua,*   

  1. aBeijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871;
    bDepartment of Chemistry, Renmin University of China, Beijing, 100872
  • Received:2026-05-25 Revised:2026-07-27
  • Contact: *E-mail: yuzx@pku.edu.cn
  • Supported by:
    NSFC-ISF (No. 22361142835) and high-performance computing platform of Peking University

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在三氟化硼促进下,苯并醌与炔烃之间可发生形式上的[6+2-1]反应生成环庚三烯酮产物,并释放一分子一氧化碳。我们的DFT计算发现,[6+2-1]反应经由炔与底物中的醌的Diels-Alder (D-A)反应引发再发生骨架重排的机理非常困难,原因是这一过程中D-A反应涉及去芳构化过程,需要非常高的活化能。为此,我们提出一种新的机理,认为反应始于炔烃对苯并醌中羰基（与BF3配位）的亲核进攻,再经过Friedel-Crafts型加成反应得到桥环[3.2.1]中间体,最后通过脱除一氧化碳分子来产生环庚三烯酮产物。这一机理得到DFT计算的支持,并可以解释为什么在使用1-烷基-2-芳基炔烃作为底物时反应能够实现较高的区域选择性。

关键词: [6+2-1]环加成, 机理研究, 苯并醌

A formal [6+2-1] reaction between benzoquinones and alkynes mediated by BF3, giving tropones and liberating carbon monoxide, was discovered by Chen previously. Report here is the mechanistic investigation of this [6+2-1] reaction through DFT calculations, finding that, the originally proposed mechanism involving energetically demanding dearomative Diels-Alder (D-A) reaction between benzoquinones and alkynes, followed by a skeleton rearrangement, is difficult. Instead, the [6+2-1] reaction starts from a nucleophilic attack of alkynes to the carbonyl of benzoquinones coordinated to BF3, followed by Friedel-Crafts type addition, giving intermediates with a [3.2.1] skeleton, which then release carbon monoxide and the final tropones. The substituent effects on the regioselectivity of this [6+2-1] reaction have also been studied when 1-alkyl2-aryl alkynes as the 2-π components were used.

Key words: [6+2-1] Cycloaddition, Mechanistic study, Benzoquinones