Tang Tianhua, Hazra Avijit, Min Daniel S, Williams Wendy L, Jones Eli, Doyle Abigail G, Sigman Matthew S
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States.
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
J Am Chem Soc. 2023 Apr 4. doi: 10.1021/jacs.3c01726.
While the oxidative addition of Ni(I) to aryl iodides has been commonly proposed in catalytic methods, an in-depth mechanistic understanding of this fundamental process is still lacking. Herein, we describe a detailed mechanistic study of the oxidative addition process using electroanalytical and statistical modeling techniques. Electroanalytical techniques allowed rapid measurement of the oxidative addition rates for a diverse set of aryl iodide substrates and four classes of catalytically relevant complexes (Ni(BPy), Ni(Phen), Ni(Terpy), and Ni(BPP)). With >200 experimental rate measurements, we were able to identify essential electronic and steric factors impacting the rate of oxidative addition through multivariate linear regression models. This has led to a classification of oxidative addition mechanisms, either through a three-center concerted or halogen-atom abstraction pathway based on the ligand type. A global heat map of predicted oxidative addition rates was created and shown applicable to a better understanding of the reaction outcome in a case study of a Ni-catalyzed coupling reaction.
虽然在催化方法中通常认为Ni(I)与芳基碘发生氧化加成反应，但对这一基本过程仍缺乏深入的机理理解。在此，我们描述了一项使用电分析和统计建模技术对氧化加成过程进行的详细机理研究。电分析技术能够快速测量多种芳基碘底物和四类催化相关配合物（Ni(BPy)、Ni(Phen)、Ni(Terpy)和Ni(BPP)）的氧化加成速率。通过200多次实验速率测量，我们能够通过多元线性回归模型确定影响氧化加成速率的重要电子和空间因素。这导致了氧化加成机理的分类，即基于配体类型通过三中心协同或卤原子抽取途径。创建了预测氧化加成速率的全局热图，并在镍催化偶联反应的案例研究中显示其适用于更好地理解反应结果。
