Selective C-Arylation of Free (NH)-Heteroarenes via Catalytic C−H Bond Functionalization
作者:Bengü Sezen、Dalibor Sames
DOI:10.1021/ja034848+
日期:2003.5.1
palladium-catalyzed arylation of a broad spectrum of free (NH)-heteroarenes has been developed (indole, pyrrole, pyrazole, 2-phenylimidazole, imidazole, benzimidazole, and purine). Remarkable selectivity has been achieved in the presence of MgO base, providing single C-arylation products, while no N-arylation and no bis-arylation products have been detected. In the case of free imidazole, exclusive C-4 arylation may
已经开发了一种用于钯催化的广谱游离 (NH)-杂芳烃(吲哚、吡咯、吡唑、2-苯基咪唑、咪唑、苯并咪唑和嘌呤)芳基化的新系统。在 MgO 碱的存在下实现了显着的选择性,提供了单一的 C-芳基化产物,而没有检测到 N-芳基化和双芳基化产物。在游离咪唑的情况下,通过将 CuI 添加到 Pd/Ph3P/MgO 体系中,可以将专有的 C-4 芳基化转换为专有的 2-芳基化。当需要游离芳基-(NH)-唑时,与标准方法相比,直接芳基化可省去三个步骤,包括 N-保护、化学计量金属化或卤化和 N-脱保护。