A chiral N,N’-dioxide/Co(BF4)2•6H2O complex catalytic system has been developed to efficiently catalyze the asymmetric 1,3-dipolar cycloaddition of nitrones with methyleneindolinones. The corresponding chiral multisubsitituted spiroisoxazolidines with three contiguous quaternary-tertiary stereocenters were obtained in moderate to high yields with excellent dr and ee values (up to 97% yield, >19:1 dr
已开发出一种手性N,N'-二氧化物/ Co(
BF4)2•6H2O络合物催化体系,可有效催化亚硝基
吲哚酮与亚硝基
吲哚酮类化合物的不对称1,3-偶极环加成反应。相应的具有三个连续的季-三级立体中心的手性多取代的螺异异唑烷类化合物以中等至高产率获得,具有优异的dr和ee值(高达97%的产率,> 19:1 dr和98%的ee)。