Key Laboratory of Characteristic Chinese Resource in Southwest China, School of Pharmacy , Chengdu University of Traditional Chinese Medicine , Chengdu , 611137 , China.
Department of Pharmacy , Naval Authorities Clinic , Beijing 100841 , China.
J Org Chem. 2019 Aug 16;84(16):10349-10361. doi: 10.1021/acs.joc.9b01501. Epub 2019 Aug 7.
A collection of chiral spirocyclic tetrahydronaphthalene (THN)-oxindole hybrids bearing a quaternary carbon center at the β-position of THN has been developed. The diastereodivergent direct catalytic Michael-aldol reaction between 3-ylideneoxindole and 2-methylbenzaldehyde was accomplished by using bifunctional tertiary amine. Simply changing the protecting group on the substrate in the organocatalytic cascade reaction led to inverted diastereoselectivity in good yields with a high ee value. To explain the diastereodivergence of the organocatalytic Michael-aldol cascade, we also proposed plausible transition-state models for [4 + 2] annulation based on the observed stereochemistry of the products.
已开发出一系列手性螺环四氢萘（THN）-氧吲哚杂合体，其在 THN 的β-位带有季碳原子中心。通过使用双功能叔胺，实现了 3-亚甲基氧吲哚与 2-甲基苯甲醛之间的非对映选择性直接催化迈克尔-Aldol 反应。在有机催化级联反应中，只需改变底物上的保护基，即可在高产率和高 ee 值的情况下获得对映选择性相反的产物。为了解释有机催化 Michael-Aldol 级联的非对映选择性，我们还根据产物的观察到的立体化学，提出了基于[4 + 2]环加成的合理过渡态模型。
