Brønsted Base and Lewis Acid Cooperatively Catalyzed Asymmetric <i>exo</i>′-Selective [3 + 2] Cycloaddition of Trifluoromethylated Azomethine Ylides and Methyleneindolinones
作者:Yang Yi、Yuan-Zhao Hua、Hui-Jie Lu、Lan-Tao Liu、Min-Can Wang
DOI:10.1021/acs.orglett.0c00283
日期:2020.4.3
3-dipolar cycloaddition is reported through chiral dinuclear zinc catalysts. An asymmetric exo′-selective [3 + 2] cycloaddition of CF3-containing N-unprotected isatin-derived azomethine ylides is realized. In the presence of 10 mol % of catalyst, azomethine ylides react efficiently with methyleneindolinones, giving a series of trifluoromethyl-substituted 2,3-pyrrolidinyl dispirooxindoles with highly enantio-
通过手性双核锌催化剂报道了布朗斯台德碱和路易斯酸协同催化的1,3-偶极环加成反应。实现了含CF 3的N-未保护的,由靛红衍生的偶氮甲碱的不对称exo'-选择性[3 + 2]环加成。在10摩尔%的催化剂存在下,甲亚胺基团与亚甲基吲哚满酮有效反应,得到一系列三氟甲基取代的2,3-吡咯烷基二螺氧基辛酮,具有高对映体(ee高达99%)和exo'选择性(> 20: 1博士)。一步即可构建多达四个连续的立体生成中心,包括两个相邻的螺旋四元立体中心。