Iron-Catalyzed CH Bond Activation for the ortho-Arylation of Aryl Pyridines and Imines with Grignard Reagents
作者:Naohiko Yoshikai、Sobi Asako、Takeshi Yamakawa、Laurean Ilies、Eiichi Nakamura
DOI:10.1002/asia.201100470
日期:2011.11.4
Direct arylation of the ortho‐CH 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 °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
所述的芳基化直接邻-C 芳吡啶或与芳基格氏试剂的芳亚胺H键已经通过使用铁二胺催化剂和二氯烷烃如在短的反应时间的氧化剂来实现(例如,5分钟)在温和的条件下(0°C)。使用芳族助溶剂(例如氯苯和苯)以及缓慢添加格氏试剂对于提高反应效率至关重要。与使用芳基锌试剂的先前开发的反应相比,本芳基化反应具有明显的优点,例如其反应速率和原子经济性。选择性C在离去基团例如对甲苯氧基,氯和溴基的存在下发生H键活化。化学计量反应和动力学同位素效应的研究为反应中间体和CH键活化步骤提供了启示。