双铑催化的[3+X](X=1-5,1+1)环加成反应的理论研究

As a kind of powerful binuclear metallic catalysts, dirhodium catalyst has been widely applied into the functionalization of C−H bond and cycloaddition, which has attracted a large amount of attention. In the decade, the experimental observation of [3+1], [3+1+1], [3+3] and [3+5] cycloaddition reactions has expanded the application of dirhodium compounds. However, not only mechanism and selectivity of those reactions are unknown, but also the role of dirhodium complex is ambiguous. All these questions and our interest in binuclear metal catalyzed cycloaddition promote us to carry out a systematically theoretical study on the reactions. In this project, the proposed mechanism of dirhodium-catalyzed [3+X] (X=1-5,1+1) would be investigatived using theoretical methods and solution translational entropy correction. With the analyses of key intermediates and transition states, the origin of selectivity and the role of catalyst would be discussed. Finally, the general principle in dirhodium-catalyzed reaction would be summarized, and the universality model for study of binuclear metal catalyzed reactions would be examined.

双铑化合物作为一种功能强大的双金属催化剂，因其能够广泛的应用到碳氢活化功能化反应和环化反应而受到人们的广泛关注。尤其是近些年随着双铑催化的[3+1]、[3+1+1]、[3+3]和[3+5]系列环加成的报道，大大促进了该类催化剂的应用。然而，这些反应是如何发生的，反应的化学和立体选择性的起源以及催化剂在反应中的作用又是怎样的，这些问题和关于双金属催化反应的研究兴趣都促使着我们对该类反应进行详细和系统的研究。申请人将密度泛函理论和液相平动熵校正方法对双铑催化的[3+X](X=1-5,1+1)环加成和相关的竞争反应进行理论模拟，通过对反应中关键结构和过渡态的分析，对催化剂的作用和催化反应的选择性进行详细的讨论。最后总结双铑催化环加成反应的一般的反应和转化的规律，建立具有普遍适用性的研究双金属催化的模型。

作为一种多中心催化剂，双铑化合物因其独特的活性而受到广泛的关注。在其转化过程中，铑卡宾的生成与转化对构建环加成反应的选择性起到了关键的作用。在这里，我们通过理论计算研究，发现金属卡宾中间体的生成与金属卡宾前驱物的作用强度相关。三氮唑类型的卡宾前驱体，一般通过混合路径完成卡宾的构建；四氮唑则更易于与催化剂结合，通过双铑催化构建金属卡宾中间体。随后金属卡宾的转化，可以构建不同大小的环加成产物。