Iron-Catalyzed C-H Bond Activation for the ortho-Arylation of Aryl Pyridines and Imines with Grignard Reagents
Iron-Catalyzed C-H Bond Activation for the ortho-Arylation of Aryl Pyridines and Imines with Grignard Reagents
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DOI：
10.1002/asia.201100470
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发表时间：
2011-11-04
影响因子：
4.1
通讯作者：
Nakamura, Eiichi
中科院分区：
文献类型：
--
作者：
Yoshikai, Naohiko;Asako, Sobi;Nakamura, Eiichi
以二氯烷烃为氧化剂，在铁-二胺催化下，芳基吡啶或芳基亚胺的邻位C-H键与芳基格氏试剂在短时间内直接芳基化。例如，在一个实施例中，5分钟）。使用芳族共溶剂，如氯苯和苯，以及缓慢加入格氏试剂对于反应的高效率是必不可少的。本芳基化反应在反应速率和原子经济性等方面均优于以往使用芳基锌试剂的芳基化反应。选择性C-H键活化在存在离去基团（例如甲苯磺酰氧基、氯和溴基团）的情况下发生。化学计量反应和动力学同位素效应的研究揭示了反应中间体和C-H键活化步骤。
Direct arylation of the ortho-C-H bond of an aryl pyridine or an aryl imine with an aryl Grignard reagent has been achieved by using an iron-diamine catalyst and a dichloroalkane as an oxidant in a short reaction time (e. g., 5 min) under mild conditions (0 degrees C). The use of an aromatic co-solvent, such as chlorobenzene and benzene, and slow addition of the Grignard reagent are essential for the high efficiency of the reaction. The present arylation reaction has distinct merits over the previously developed reaction that used an arylzinc reagent, such as its reaction rate and atom economy. Selective C-H bond activation occurs in the presence of a leaving group, such as a tosyloxy, chloro, and bromo group. Studies on a stoichiometric reaction and kinetic isotope effects shed light on the reaction intermediate and the C-H bond-activation step.