Reddy Reddy Rajasekhar, Gayen Prasenjit, Panda Shibaram, Ghorai Prasanta
Department of Chemistry , Indian Institute of Science Education and Research (IISER) Bhopal , Bhopal By-pass Road , Bhauri , Bhopal 462066 , India.
Org Lett. 2019 Aug 2;21(15):5793-5797. doi: 10.1021/acs.orglett.9b01705. Epub 2019 Jul 12.
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 (up to 99:1 dr and 99% ee). Notably, a complete chemoselective addition of a methylene unit to an aliphatic-tethered enone over the aromatic-tethered enone was observed.
已开发出一种前所未有的对映选择性不对称1,4 - 和1,2 - 丙二腈加成到酮双烯酮上，随后进行氧杂 - 迈克尔加成级联反应以捕获原位生成的不稳定叔醇的反应。奎宁衍生的氨基方酰胺双功能有机催化剂高效工作，以良好的产率和优异的非对映和对映选择性（高达99:1的非对映体比例和99%的对映体过量）提供氧杂 - 螺[4,4]壬烷。值得注意的是，观察到亚甲基单元完全化学选择性地加成到脂肪族连接的烯酮上，而不是芳香族连接的烯酮上。
