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中国科学院大学学报 ›› 2022, Vol. 39 ›› Issue (2): 145-153.DOI: 10.7523/j.ucas.2021.0046

• 前沿创新 •    下一篇

钯催化α,β-不饱和酰氯与炔烃合成环戊烯酮模块化策略机理的密度泛函理论计算(英文)

钟亮, 赵瑞华, 汪志祥   

  1. 中国科学院大学化学科学学院, 北京 100049
  • 收稿日期:2021-04-19 修回日期:2021-05-19 发布日期:2022-03-17
  • 通讯作者: 汪志祥
  • 基金资助:
    Supported by the National Natural Science Foundation of China (21773240)

DFT mechanistic insight into the modular strategy involved in the palladium-catalyzed synthesis of cyclopentenones from α,β-unsaturated acid chlorides and alkynes

ZHONG Liang, ZHAO Ruihua, WANG Zhixiang   

  1. School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-04-19 Revised:2021-05-19 Published:2022-03-17
  • Supported by:
    Supported by the National Natural Science Foundation of China (21773240)

摘要: 环戊烯酮是重要的有机合成原料,也是生物活性化合物和天然产物构建模块。采用密度泛函理论计算,本文研究以硅烷为氢源,钯催化α,β-不饱和酰氯与炔烃合成环戊烯酮的模块化策略的机理。研究表明该反应经下面过程顺序进行:钯催化剂拆分酰氯成烯基、羰基和氯单元;一氧化碳释放;炔烃与烯基偶联;一氧化碳重新配位和迁移插入形成另一个C—C键;经C=C双键迁移插入关环,与氢硅烷发生转金属反应,C,H-还原消除释放产物。该机理与实验工作者提出的机理不同,羰基通过在溶剂笼中释放和重新配位参与反应,而不是一直与钯配位。转金属H/Cl交换发生在反应后期,是反应的瓶颈过程, 而不是发生在前期的酰氯拆分。

关键词: 环戊烯酮合成, 模块化策略, 一氧化碳替代, 钯催化, 密度泛函理论计算

Abstract: Cyclopentenones are important synthetic building blocks and as motifs appear in bioactive molecules and natural products. We applied density functional theory (DFT) calculations to gain insight into the modular strategy involved in the palladium-catalyzed synthesis of cyclopentenone from α,β-unsaturated acid chlorides and alkynes in the presence of hydrosilane. The study unveils that the transformation proceeds via the sequence:the disassembly of α,β-unsaturated acid chloride into vinyl, carbonyl, and Cl fragments with the palladium catalyst; carbon monoxide release; coupling of alkyne with vinyl group; carbon monoxide re-coordination and migratory insertion to form another C-C bond with alkyne, ring-closure via C=C bond insertion, transmetalation with hydrosilane, C, H-reductive elimination to release the product. Different from the mechanism proposed by the experimentalists, the CO group is involved in the reaction via separate liberation and re-coordination in the solvent cage, rather than persistent coordination with palladium. The transmetalation for H/Cl exchange takes place at the late stage and is a bottleneck of the transformation, instead of at early disassembly stage.

Key words: cyclopentenone synthesis, modular strategy, carbon monoxide surrogates, palladium catalysis, DFT calculation

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