An unprecedented strategy to access highly enantioenriched dihydropyrazoles is described. It involves formal [4+1] cycloadditions of in situ-derived azoalkenes and sulfurylides catalyzed by a chiral copper/Tol-BINAP complex. A variety of synthetically and biologically important dihydropyrazoles have been obtained with high enantioselectivities (up to 97:3 er) in good yields (83-97%).
Protecting group-directed annulations of tetra-substituted oxindole olefins and sulfur ylides: regio- and chemoselective synthesis of cyclopropane- and dihydrofuran-fused spirooxindoles
作者:Jing-Wen Kang、Xiang Li、Fei-Yu Chen、Yuan Luo、Shu-Cang Zhang、Bin Kang、Cheng Peng、Xu Tian、Bo Han
DOI:10.1039/c9ra02192b
日期:——
Protecting group-controlled annulations of tetra-substituted oxindole olefins and sulfur ylides have been achieved for the synthesis of multifunctional cyclopropane- and dihydrofuran-fused spirooxindoles. Under precise annulation regulation, a variety of cyclopropane- and dihydrofuran-fused spirooxindoles containing vicinal quaternary carbon centers were produced in up to 90% yield with up to 20 : 1
已经实现了四取代羟吲哚烯烃和硫叶立德的保护基控制环化,用于合成多功能环丙烷和二氢呋喃稠合螺羟吲哚。在精确的环化调节下,以高达 90% 的产率和高达 20 : 1 的 dr. 该反应表现出高区域、化学和非对映选择性、广泛的官能团耐受性和克级容量。