发现Pd(OAc)2在非常低的催化剂负载量和无膦条件下,可以非常有效地催化咪唑并[1,2- b ]哒嗪在C3位上的直接芳基化。该反应可以在非常高的TOF和TON中进行,使用的芳基溴化物种类繁多,催化剂用量低至0.1-0.05 mol%。此外,还发现一些缺电子的芳基氯化物是合适的底物。此外,报告了使用绿色,安全和可再生溶剂(例如戊烷-1-醇,碳酸二乙酯或环戊基甲基醚)的31个交叉偶联实例,而没有降低效率。
Direct Arylation of Imidazo[1,2-<i>b</i>]pyridazines: Microwave-Assisted One-Pot Suzuki Coupling/Pd-Catalysed Arylation
作者:Ahmed El Akkaoui、Sabine Berteina-Raboin、Abderrahim Mouaddib、Gérald Guillaumet
DOI:10.1002/ejoc.200900849
日期:2010.2
Direct intermolecular C-H arylation of 6-chloroimidazo[1,2-b]-pyridazine in its 3-position was achieved, and the tolerance to reaction conditions in the presence of chloro groups was investigated. Various 3-(hetero)arylimidazo[1,2-b]pyridazines were synthesized in good to excellent yields. This methodology was successfully applied to the synthesis of 3,6-di-and 2,3,6-trisubstituted imidazo[1,2-b]pyridazines