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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Selectivity control of Pd(PMe3)(4)-catalyzed hydrogenation of internal alkynes to E-alkenes by reaction time and water content in formic acid
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Selectivity control of Pd(PMe3)(4)-catalyzed hydrogenation of internal alkynes to E-alkenes by reaction time and water content in formic acid

机译：Pd（PME3）（4）的选择性控制 - 通过反应时间和甲酸水含量来催化内醇对E-烯烃的氢化

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摘要

The modulation of selectivity of transfer hydrogenation of alkynes to E-alkenes using formic acid is a challenge due to the limited knowledge of the complex reaction network, including oxidative addition, decarboxylation, reductive elimination, Z -> E isomerization, and beta-H elimination. Here, the search for the reaction pathway and experiment explorations revealed that the selectivity of Pd(PMe3)(4)-catalyzed hydrogenation of 1-phenyl-1-propyne to (E)-1-phenylpropene is controlled by the water content in the aqueous solution of formic acid and the reaction time. The combination of an automatic reaction pathway search and density functional theory (DFT) calculations found that the intermolecular hydrogen bonds with water molecules have an influence on lowering the free energy activation barrier of transition states in the oxidative addition steps. The reasonable reaction barriers of Z -> E isomerization and hydrogenation result in the dependence of selectivity on reaction time, which has been supported by experiments. By using molecular sieves, the water in formic acid is removed, and the yield of the desired (Z)-1-phenylpropene product increases to the highest value (86%) in 5 hours but decreases to 54% when the reaction is run for 16 hours due to the further Z -> E isomerization and hydrogenation. In the second stage which starts from (Z)-1-phenylpropene, the yield of (E)-1-phenylpropene decreased from 90% (with 4 angstrom MS) to 67% in the aqueous solution of formic acid.
机译：由于复杂反应网络的知识有限，包括氧化添加，脱羧，还原消除，Z - > E异构，Z - > E异构化和β-H消除，因此使用甲酸转移到E-烯烃的选择性对E-烯烃的选择性是一种挑战，包括氧化添加，脱羧，还原消除，Z - > E异构化和β-H消除。这里，对反应途径和实验探索的搜索显示，Pd（PME3）（4）的选择性 - 催化1-苯基-1-丙基至（E）-1-苯基丙烯的催化剂由水含量控制甲酸水溶液和反应时间。自动反应途径搜索和密度官能理论（DFT）计算的组合发现，与水分子的分子间氢键对降低氧化添加步骤中的过渡状态的自由能活化屏障有影响。 Z - > E异构化和氢化的合理反应屏障导致选择性对反应时间的依赖性，这已通过实验支持。通过使用分子筛，除去甲酸中的水，所需的（Z）-1-苯丙烯产物的产率在5小时内增加到最高值（86％），但是当反应运行时减少至54％由于进一步的Z - > E异构化和氢化，16小时。在从（Z）-1-苯基丙烯开始的第二阶段，（e）-1-苯基丙烯的产率在甲酸水溶液中从90％（具有4埃MS）降低至67％。

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    Wang Wenmin; Gao Liuzhou; Wei Haiyan; Qi Zheng-Hang; Zeng Guixiang; Cheng Xu; Wang Guoqiang; Ma Jing;

  • 作者单位

    Nanjing Univ Sch Chem &

    Chem Engn Key Lab Mesoscop Chem MOE 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Univ Sch Chem &

    Chem Engn Key Lab Mesoscop Chem MOE 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Normal Univ Jiangsu Collaborat Innovat Ctr Biomed Funct Mat Jiangsu Prov Key Lab NSLSCS Jiangsu Key Lab Biomed Mat Sch Chem &

    Mat Sci Nanjing 210046 Jiangsu Peoples R China;

    Nanjing Univ Sch Chem &

    Chem Engn Key Lab Mesoscop Chem MOE 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Univ Kuang Yaming Honors Sch Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Univ Sch Chem &

    Chem Engn Jiangsu Key Lab Adv Organ Mat 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Univ Sch Chem &

    Chem Engn Key Lab Mesoscop Chem MOE 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

    Nanjing Univ Sch Chem &

    Chem Engn Key Lab Mesoscop Chem MOE 163 Xianlin Rd Nanjing 210023 Jiangsu Peoples R China;

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  • 正文语种 eng
  • 中图分类 化学;无机化学;
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