Quinine-catalyzed asymmetric domino Michael-cyclization reaction for the synthesis of spirocyclic oxindoles bearing two spiro quaternary centers and three consecutive stereocenters
作者:Bao-Dong Cui、Shi-Wu Li、Jian Zuo、Zhi-Jun Wu、Xiao-Mei Zhang、Wei-Cheng Yuan
DOI:10.1016/j.tet.2014.01.036
日期:2014.3
An efficient organocatalytic diastereo- and enantioselective method for the construction of spirocyclic oxindole derivatives bearing two spiro quaternary centers and three consecutive stereocenters via a domino Michael/cyclization process has been developed. Using commercially available quinine as catalyst, the reactions of 3-isothiocyanato oxindoles with unsaturated pyrazolones and unsaturated isoxazolones
已开发出一种有效的有机催化非对映和对映体选择性方法,用于通过多米诺米歇尔/环化过程构建带有两个螺环季铵盐中心和三个连续立体中心的螺环环氧吲哚衍生物。使用市售的奎宁作为催化剂,3-异硫氰酸根合吲哚类化合物与不饱和吡唑啉酮和不饱和异恶唑酮类的反应在温和的反应条件下顺利进行,从而以高至优异的收率得到两类螺环恶吲哚化合物,具有中等至良好的非对映选择性和对映选择性。暂时提出了一个可行的双重激活工作模型来说明多米诺米歇尔/环化过程的立体化学。