作者:Mylène de Léséleuc、Shawn K. Collins
DOI:10.1021/acscatal.5b00082
日期:2015.3.6
Efficient direct macrolactonization of seco acids can be catalyzed by Hf(OTf)4 in high yields, forming water as the sole byproduct. The Hf(OTf)4 catalyst possesses unique reactivity characteristics relative to other Lewis acids, as it promotes macrolactonization over hydrolysis even in the presence of excess water. In addition to forming a variety of macrolactones and benzolactones (55–90%), intermolecular
Hf(OTf)4可以高产率催化山梨酸的高效直接大环内酯化,形成水作为唯一的副产物。Hf(OTf)4相对于其他路易斯酸,该催化剂具有独特的反应特性,因为即使在存在过量水的情况下,它也比水解作用促进大内酯化。除了形成各种大分子内酯和苯并内酯(55-90%)外,羧酸和醇的分子间直接酯化也是可能的,并证明了与常见的氨基甲酸酯,甲硅烷基醚,烷氧基甲基醚和乙缩醛保护基的相容性。开发的所有大环内酯化和酯化方法都是操作简单的“一锅法”反应,可利用市售催化剂,而无需缓慢添加或共沸技术。