Graduate School of Science, ‡JST-ERATO, Itami Molecular Nanocarbon Project and §Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Chikusa, Nagoya 464-8602, Japan.
J Am Chem Soc. 2018 Feb 14;140(6):2196-2205. doi: 10.1021/jacs.7b11260. Epub 2018 Jan 30.
The transition-metal-catalyzed C-H arylation of aromatic hydrocarbons represents a useful and ideal method for the production of biaryls and multiarylated aromatic compounds. We have previously reported the palladium-catalyzed direct C-H arylation of polycyclic aromatic hydrocarbons, such as phenanthrene, pyrene, and corannulene with various organosilicon, -borane, and -germanium compounds. In these reactions, o-chloranil proved to be an essential and unique promoter (stoichiometrically as an oxidant) and arylation occurred exclusively at the K-region. Herein, we report our mechanistic investigation of Pd/o-chloranil catalysis in C-H arylation of phenanthrene with trimethylphenylsilane by computational calculations. The results revealed that C-H arylation occurs through a sequence of transmetalation, carbometalation, and trans-β-hydrogen elimination steps. In addition, the triple role of o-chloranil as a ligand, oxidant, and base is also elucidated.
过渡金属催化的芳烃 C-H 芳基化反应是一种生产联芳烃和多芳基芳烃化合物的有用且理想的方法。我们之前已经报道了钯催化的多环芳烃，如菲、芘和corannulene与各种有机硅、-硼烷和-锗化合物的直接 C-H 芳基化反应。在这些反应中，邻氯过氧苯甲酸被证明是一种必不可少的独特促进剂（作为氧化剂以化学计量比使用），芳基化仅在 K-区域发生。在此，我们通过计算化学研究了邻氯过氧苯甲酸促进的钯催化的三甲基苯基硅烷与菲的 C-H 芳基化反应的机理。结果表明，C-H 芳基化反应通过转金属化、碳金属化和反式-β-氢消除步骤进行。此外，还阐明了邻氯过氧苯甲酸作为配体、氧化剂和碱的三重作用。
