过渡金属催化亚甲基环丙烷C-C键断裂机理及选择性的理论研究

Selective synthesis of different products from the same materials by just choosing different catalysts is an interesting research topic for chemists. Methyleneeyclopropanes (MCPs), highly strained but readily accessible molecules, have been proven to be useful synthetic intermediates with nice reactivates and selectivity because the relief of ring strain provides a potent thermodynamic driving force. Methyleneeyclopropanes (MCPs) are also often used as synthetic intermediates in the preparation of acyclic, carbocyelic and heterocyelic compounds. Therefore, there has been much effort aimed at the development of synthetic methodology for the efficient preparation of methyleneeyclopropanes. In this research , we would chose several typical reactions that have been carefully studied using quantum methods，obtained some interesting results．On the basis of the molecular orbital theory, the tradition transition state theory as well as quantum chemistry theory, the systems chose have been investigated using Density Functional (DFT)Theory, the polarized continuum model(PCM) and the natural bond orbital(NBO).The structures of the reagents，the reaction products and the transition states along the reaction paths would been obtained，then obtained the reaction surfaces, the spectrum datum，the thermodynamic datum as well as the information of orbital. The reaction mechanism has been argued deeply using these data．

本课题利用密度泛函理论、从头算方法以及QM/QM(MM) 方法对过渡金属配合物催化亚甲基环丙烷C-C键断裂的机理及选择性进行理论研究。基于目前该领域所亟需解决的反应活性以及C-C键断裂选择机理的系列基础性问题，深入研究体系反应活性中心，阐明过渡金属自身性质（包括金属中心和配体）与反应活性以及C-C键断裂选择机理之间的关系，揭示底物中取代基的导引竞争，导引协同，以及电子效应和位阻效应对反应的影响，整体考虑不同过渡金属催化下以及溶剂参与效应对反应活性及C-C键断裂选择机理的协同影响。本课题研究将建立有效的反应机理和C-C键断裂竞争选择机理，为预测体系的最终产物和设计新型过渡金属催化亚甲基环丙烷C-C键断裂体系提供理论指导，并为过渡金属配合物催化亚甲基环丙烷C-C键断裂的机理及选择性反应的可调控的实现打下理论基础。另外，项目中关于溶剂参与效应的研究，将为模拟真实体系的反应机理提供新的研究方法。

过渡金属配合物催化亚甲基环丙烷C-C键断裂的实验已经有了详细的研究。然而基于目前该领域所亟需解决的反应活性以及C-C键断裂选择机理的系列基础性问题，尤其是体系反应活性中心，过渡金属自身性质（包括金属中心和配体）与反应活性以及C-C键断裂选择机理之间的关系等却很少有理论报道。我们选取一价金和二价铂催化剂，同时选取了重要的金属配体氮杂卡宾对其在催化反应中的活性中心，以及反应的区域选择性进行了详细的理论计算。以分子轨道理论和过渡态理论为基础，揭示了底物中取代基的导引竞争，导引协同，以及电子效应和位阻效应对反应的影响。为预测体系的最终产物和设计新型过渡金属催化体系提供理论指导，并为过渡金属配合物催化反应的可调控的提供了新的思路与方法。在以上工作的基础上，我们和实验组合作，对一价金和二价钯催化反应初步实现了理论与实验相结合。为后面的进一步合作提供了较好的工作基础