Optically active spirocyclohexaneoxindole motifs are very important building blocks for preparations of biologically active complexes, natural products, and pharmaceutical compounds. Herein, we report the syntheses of enantiopure spirocyclohexaneoxindoles through domino MichaelâAldol reactions between isatin derived alkenes and pentane-1,5-dial in the presence of diphenylprolinol silyl ether as an aminocatalyst. As a result, a series of multistereogenic and functionalized spirocyclohexaneoxindoles have been obtained in good yields with moderate diastereoselectivities and excellent enantioselectivities. In addition, electronic circular dichroism (ECD) spectroscopy and time-dependent density functional theory (TD-DFT) were used to investigate the rational structures of spirocyclohexaneoxindoles.
光学活性螺环己氧
吲哚基序是制备
生物活性复合物、
天然产物和药物化合物的非常重要的构建模块。在此,我们报道了在二苯基脯
氨醇甲
硅烷基醚作为
氨基催化剂存在下,通过
靛红衍生的烯烃和1,5-二元
戊烷之间的多米诺迈克尔·羟醛反应合成对映体纯螺
环己烷吲哚。结果,我们以良好的产率获得了一系列具有中等非对映选择性和优异对映选择性的多立体和官能化螺环己氧
吲哚。此外,电子圆二色性(
ECD)光谱和时间相关密度泛函理论(TD-DFT)被用来研究螺环己氧
吲哚的合理结构。