Phosphine-Catalyzed Chemo- and Diastereoselective [2 + 2 + 2] and [3 + 2] Annulations of γ-Methyl Allenoates with Doubly Activated Olefins: Syntheses of Highly Substituted Cyclohexanes and Cyclopentenes
作者:Rongfang Liu、Zifeng Qin、Binbin Fan、Ruifeng Li、Rong Zhou、Zhengjie He
DOI:10.1021/acs.joc.9b01968
日期:2019.10.4
Phosphine-catalyzed chemoselective [2 + 2 + 2] and [3 + 2] annulations of γ-methyl allenoates with doubly activated olefins have been developed, which afford highly substituted cyclohexanes bearing five continuous stereogenic centers and cyclopentenes bearing three continuous stereogenic centers, respectively, in generally high yields with excellent diastereoselectivity. The [2 + 2 + 2] annulation represents an unprecedented
已开发出具有双活化烯烃的膦催化化学选择性的[2 + 2 + 2]和[3 + 2]环烷基,可分别提供带有五个连续立体中心的高取代环己烷和带有三个连续立体中心的环戊烯,通常具有高非对映选择性的高收率。[2 + 2 + 2]环空表示具有激活C═C键的六元碳环的γ-甲基脲酸酯的空前反应模式。另外,本文的研究还证明酸性质子添加剂如苯甲酸可影响膦催化的涉及烯丙酸酯的环化反应的化学选择性。