高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (3): 521-529.doi: 10.7503/cjcu20170405

• 物理化学 • 上一篇    下一篇

铑(Ⅰ)催化烯烃碳酰化反应机理: 手性聚稠环过程的对映选择性

程学礼1(), 李衍飞1, 赵燕云1, 刘永军2()   

  1. 1. 泰山学院化学化工学院, 泰安 271000
    2. 山东大学化学化工学院, 济南 250100
  • 收稿日期:2017-06-26 出版日期:2018-03-10 发布日期:2018-01-17
  • 作者简介:联系人简介: 程学礼, 男, 博士, 教授, 主要从事金属有机催化理论研究. E-mail:ching108@sohu.com; x_cheng@tsu.edu.cn;刘永军, 男, 博士, 教授, 博士生导师, 主要从事理论与计算化学研究. E-mail:yongjunliu_1@sdu.edu.cn
  • 基金资助:
    国家自然科学基金(批准号: 21502136, 21571137, 51702228)、 山东省自然科学基金(批准号: ZR2017LB010)和泰山学院引进人才科研启动基金(批准号: Y-01-2013010)资助

Reaction Mechanism of Rh(I)-catalyzed Olefin Carboacylation:Enantioselectivity in the Formation of Chiral Poly-fused Rings

CHENG Xueli1,*(), LI Yanfei1, ZHAO Yanyun1, LIU Yongjun2,*()   

  1. 1. School of Chemistry and Chemical Engineering, Taishan University, Tai’an 271000, China
    2. School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
  • Received:2017-06-26 Online:2018-03-10 Published:2018-01-17
  • Contact: CHENG Xueli,LIU Yongjun E-mail:ching108@sohu.com;x_cheng@tsu.edu.cn;yongjunliu_1@sdu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.21502136, 21571137, 51702228), the Natural Science Foundation of Shandong Province, China(No.ZR2017LB010) and the Scientific Research Initial Foundation for Introduction of Talent of Taishan Universities, China(No.Y01-2013010)

摘要:

采用密度泛函理论方法研究了[Rh(R,R-DIOP)]+[DIOP=(1R,2R)-1,2-O-异丙叉-1,2-二醚氧基-1,2-双(二苯基磷基)乙烷]催化下苯并环丁酮手性聚稠环过程在气相、 四氢乙呋喃(THF)及水中的反应机理. 计算结果表明, 在气相中反应容易进行, 经TS2形成六元环的过程为决速步骤, 但产物无明显的对映选择性. 在THF中, S-和R-通道的C—C键活化能垒仅由79.5和69.3 kJ/mol提高到80.2和88.8 kJ/mol, 未改变反应的实质; Rh与2个C原子的配位明显弱于气相, 相对于催化剂和反应物自由能之和, S-和R-通道的反应总能垒分别提高到63.8和68.1 kJ/mol. 对于S-通道, 溶剂THF使经TS2的能垒升至112.0 kJ/mol, 仍为整个过程的决速步骤; 然而对R-通道, 溶剂使经TS1形成五元环过程的能垒升至91.5 kJ/mol, 但使经TS2的能垒由78.9 kJ/mol降至77.7 kJ/mol, IM1→TS1成为决速步骤. 在以水为溶剂时, 经TS1形成五元环的过程成为2个通道的决速步骤, 其在S-和R-通道中的能垒分别为102.5和94.9 kJ/mol. 因此, 溶剂改变了反应的决速步骤及能垒. 3种方法均预测R-通道为主反应路径, 但THF能明显增加产物的对映选择性. 采用自然键轨道(NBO)电荷分析了反应过程中电荷的变化.

关键词: 烯烃碳酰化, [Rh(R, R-DIOP)]+, 对映选择性, 手性聚稠环

Abstract:

Density functional theory(DFT) methods were employed to investigate the reaction mechanisms of the formation of chiral poly-fused rings of benzocyclobutenone catalyzed by [Rh(R,R-DIOP)]+ in gas phase, THF and water. The theoretical results show that, the reaction system will proceed easily in gas phase, and the formation of the six-membered rings via TS2 is the rate-determining step, but the products are no distinct enantioselectivity. For the S- and R-channels in THF, the free energy barriers of C—C activation are elevated slightly from 79.5 and 69.3 kJ/mol to 80.2 and 88.8 kJ/mol, respectively, but do not alter the reaction characters. The coordination of Rh with the two C atoms is much weaker than that in gas phase, and the total free-energy barriers relative to the catalyst and the reactant in the S- and R-pathways are increased to 63.8 and 68.1 kJ/mol. For the S-channel, THF as solvent markedly increases the barrier via TS2 to 112.0 kJ/mol, and the process is still the rate-determining step. However, to the R-pathway, THF increases the barrier of forming the five-membered ring to 91.5 kJ/mol, but decreases the barrier via TS2 from 78.9 kJ/mol to 77.7 kJ/mol, so IM1→TS1 becomes the rate-determining step. When employing water as the solvent, the formation of the five-membered rings via TS1 becomes the rate-determining steps of these two reaction pathways, and the barriers of the S- and R-channels are 102.5 and 94.9 kJ/mol. As a result, solvents alter the rate-determining steps and their energy barriers of the reaction system. All these 3 methods predict that the R-pathway is the predominated reaction channel, but THF can evidently increase the enantioselectivity. The charge population was also analyzed by using the natural bond orbital(NBO) charges.

Key words: Olefin carboacylation, [Rh(R, R-DIOP)]+, Enantioselectivity, Poly-fused ring

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