The mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second-order Moller-Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, ...The mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second-order Moller-Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, vibrational analysis and energetics have been calculated for the involved stationary points on the potential energy surface. The results show that the title reaction has two major competition channels. An energy-rich intermediate (INT) is firstly formed between alkylidene carbene and ethylene through a barrier-free exothermic reaction of 63.62 kJ/mol, and the intermediate then isomerizes to a three-membered ring product (Pl) and a four-membered ring product (P2) via transition state TS1 and TS2, in which energy barriers are 47.00 and 51.02 kl/mol. respectively. PI is the main product.展开更多
An N-heterocyclic carbene(NHC)-catalyzed enantioselective Mannich reaction of the remoteγ-carbon of cyclopropylcarbaldehydes is disclosed for the first time.Diastereo-and enantiomerically enriched multicyclicδ-lacta...An N-heterocyclic carbene(NHC)-catalyzed enantioselective Mannich reaction of the remoteγ-carbon of cyclopropylcarbaldehydes is disclosed for the first time.Diastereo-and enantiomerically enriched multicyclicδ-lactam compound is afforded as the main product from 8 possible stereo-specific isomers through dynamic kinetic asymmetric transformation(DYKAT)processes.Multiple chiral functional molecules can be afforded from the lactam products through simple protocols with retentions of the optical purities.展开更多
以负载氯化亚铜为催化剂,研究了苯乙烯和四氯化碳加成反应的动力学,为工业反应过程的开发和操作提供了理论依据。在本实验条件下,催化剂的粒径为10 8～10 7m,内扩散影响可以忽略。当搅拌速度大于210 r min 1时,外扩散影响基本消除,反应...以负载氯化亚铜为催化剂,研究了苯乙烯和四氯化碳加成反应的动力学,为工业反应过程的开发和操作提供了理论依据。在本实验条件下,催化剂的粒径为10 8～10 7m,内扩散影响可以忽略。当搅拌速度大于210 r min 1时,外扩散影响基本消除,反应进入动力学控制区。系统地测定了65～75℃下的反应动力学数据。依据自由基加成反应机理和单活性位吸附的假设,建立了动力学模型,rA=K[CA][CB]+k1[CB]。对实验数据进行非线性拟合,得到反应动力学模型参数。计算得到其控制步骤解离吸附的反应活化能为1.11×105kJ mol 1。动力学模型与实验数据吻合较好,在实验范围内可信度较高。展开更多
基金the Natural Science Foundation of Shandong Province of China (No. Y2002B07).
文摘The mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second-order Moller-Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, vibrational analysis and energetics have been calculated for the involved stationary points on the potential energy surface. The results show that the title reaction has two major competition channels. An energy-rich intermediate (INT) is firstly formed between alkylidene carbene and ethylene through a barrier-free exothermic reaction of 63.62 kJ/mol, and the intermediate then isomerizes to a three-membered ring product (Pl) and a four-membered ring product (P2) via transition state TS1 and TS2, in which energy barriers are 47.00 and 51.02 kl/mol. respectively. PI is the main product.
基金This work was supported by the National Natural Science Foundation of China(21772029,21801051,21961006,22071036,82360589,81360589)The 10 Talent Plan(Shicengci)of Guizhou Province([2016]5649)+5 种基金the Guizhou Province Returned Oversea Student Science and Technology Activity Program[(2014)-2]the Science and Technology Department of Guizhou Province([2018]2802,[2019]1020)the Program of Introducing Talents of Discipline to Universities of China(111 Program,D20023)at Guizhou University,Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules,Department of Education,Guizhou Province[Qianjiaohe KY(2020)004]the Guizhou Province First-Class Disciplines Project[(Yiliu Xueke Jianshe Xiangmu)-GNYL(2017)008]Guizhou University of Traditional Chinese Medicine(China),and Guizhou University.
文摘An N-heterocyclic carbene(NHC)-catalyzed enantioselective Mannich reaction of the remoteγ-carbon of cyclopropylcarbaldehydes is disclosed for the first time.Diastereo-and enantiomerically enriched multicyclicδ-lactam compound is afforded as the main product from 8 possible stereo-specific isomers through dynamic kinetic asymmetric transformation(DYKAT)processes.Multiple chiral functional molecules can be afforded from the lactam products through simple protocols with retentions of the optical purities.
文摘以负载氯化亚铜为催化剂,研究了苯乙烯和四氯化碳加成反应的动力学,为工业反应过程的开发和操作提供了理论依据。在本实验条件下,催化剂的粒径为10 8～10 7m,内扩散影响可以忽略。当搅拌速度大于210 r min 1时,外扩散影响基本消除,反应进入动力学控制区。系统地测定了65～75℃下的反应动力学数据。依据自由基加成反应机理和单活性位吸附的假设,建立了动力学模型,rA=K[CA][CB]+k1[CB]。对实验数据进行非线性拟合,得到反应动力学模型参数。计算得到其控制步骤解离吸附的反应活化能为1.11×105kJ mol 1。动力学模型与实验数据吻合较好,在实验范围内可信度较高。
