Chiral Squaramide-Catalyzed Sulfa-Michael/Aldol Cascade for the Asymmetric Synthesis of Spirocyclic Tetrahydrothiophene Chromanone Derivatives
作者:Bo-Liang Zhao、Lei Liu、Da-Ming Du
DOI:10.1002/ejoc.201402889
日期:2014.12
A bifunctional squaramide-catalyzed sulfa-Michael/aldol cascade reaction between benzylidenechroman-4-ones and 1,4-dithiane-2,5-diol with a low catalyst loading has been developed. This reaction constitutes a facile asymmetric synthesis of chiral spirocyclic tetrahydrothiophene chromanone derivatives with three contiguous stereocenters in high to excellent yields (up to 99 %) and with high enantioselectivities
已经开发了一种双功能方酸酰胺催化的苯亚甲基色满-4-酮和 1,4-二噻烷-2,5-二醇之间的低催化剂负载量的磺胺-迈克尔/醛醇级联反应。该反应构成了具有三个连续立体中心的手性螺环四氢噻吩色满酮衍生物的简便不对称合成,产率高至极好(高达 99%)和高对映选择性(高达 92%ee)。此外,观察到温度对反应效率的显着影响,并且发现克规模合成以与较小规模反应相同的效率顺利进行。