Enantioselective, Organocatalytic, Dissymmetric 1,4- and 1,2-Addition of Malononitrile to a Keto-bisenone Followed by an Oxa-Michael Addition Cascade
作者:Reddy Rajasekhar Reddy、Prasenjit Gayen、Shibaram Panda、Prasanta Ghorai
DOI:10.1021/acs.orglett.9b01705
日期:2019.8.2
An unprecedented enantioselective dissymmetric 1,4- and 1,2-addition of malononitrile to a keto-bisenone followed by an oxa-Michael addition cascade to trap the in situ generated unstable tertiary alcohol have been developed. The quinine-derived amino-squaramide bifunctional organocatalyst worked efficiently and provides the oxa-spiro-[4,4]-nonanes in good yields and excellent diastereo- and enantioselectivities
已经开发出前所未有的对映选择性不对称的丙二腈向酮-双烯酮的1,4-和1,2-加成,然后进行氧杂-Michael加成级联以捕获原位生成的不稳定叔醇。奎宁衍生的氨基-方酰胺双功能有机催化剂有效地工作,并提供了高收率的氧杂-螺-[4,4]-壬烷,非对映和对映选择性(高达99:1 dr和99%ee)。值得注意的是,观察到在芳族连接的烯酮上将亚甲基单元完全化学选择性加成到脂族连接的烯酮上。