Highly Ligand-Controlled Regioselective Pd-Catalyzed Aminocarbonylation of Styrenes with Aminophenols
作者:Tongyu Xu、Feng Sha、Howard Alper
DOI:10.1021/jacs.6b03161
日期:2016.5.25
Achieving chemo- and regioselectivity simultaneously is challenging in organic synthesis. Transition metal-catalyzed reactions are effective in addressing this problem by the diverse ligand effect on the catalyst center. Ligand-controlled regioselective Pd-catalyzed carbonylation of styrenes with aminophenols was realized, chemoselectively affording amides. Using a combination of boronic acid and 5-chlorosalicylic
同时实现化学选择性和区域选择性在有机合成中具有挑战性。过渡金属催化的反应通过对催化剂中心的多种配体效应有效地解决了这个问题。实现了配体控制的区域选择性 Pd 催化苯乙烯与氨基酚的羰基化,化学选择性地提供酰胺。使用硼酸和 5-氯水杨酸的组合作为添加剂,在乙腈中使用三(4-甲氧基苯基)膦(L3)以高收率和选择性获得直链酰胺,而在丁酮中以高收率和选择性获得支链酰胺通过将配体更改为 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phosphaadamantane (L5)。进一步的研究表明,配体的性质是区域选择性的关键。锥角和托尔曼电子参数 (TEP) 与反应性和区域选择性相关。对酸添加剂的研究表明,不同的酸作为质子源,相应的反离子有助于提高反应性和选择性。