Chiral Brønsted Base Activation of Donor–Acceptor Cyclopropanes toward Diastereo- and Enantioselective [3 + 2] Cycloaddition with Isatin-Derived Ketimines,The Journal of Organic Chemistry

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Chiral Brønsted Base Activation of Donor–Acceptor Cyclopropanes toward Diastereo- and Enantioselective [3 + 2] Cycloaddition with Isatin-Derived Ketimines
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2024-06-10 , DOI: 10.1021/acs.joc.4c00614
Zhe-Jia Yu ₁ , Shuang Yan ₁ , Xiao-Li Zhao ₂ , Jun Zhang ₁ , Mei-Xin Zhao ₁

Affiliation

Organocatalyzed diastereo- and enantioselective [3 + 2] cycloaddition reactions of donor–acceptor (D–A) cyclopropanes with isatin-derived ketimines are presented. Different from well-developed Lewis acid activation protocols which promote the reactivity of D–A cyclopropanes through coordinating to the acceptor group, in this reaction, dicyanocyclopropylmethyl ketones can be activated through nucleophilic activation of the donor group by using dihydroquinine-derived squaramide as Brønsted base catalyst. The reaction affords functionalized spiro[oxindole-3,2′-pyrrolidines] with two nonadjacent tetra- and tri-substituted stereocenters in 83–99% yields, moderate to excellent diastereoselectivities (up to >20:1 diastereomeric ratio (dr)), and excellent enantioselectivities (up to >99% enantiomeric excess (ee)) under mild conditions.

中文翻译：

供体-受体环丙烷的手性布朗斯台德碱活化与靛红衍生的酮亚胺的非对映和对映选择性 [3 + 2] 环加成反应

提出了供体-受体 (D-A) 环丙烷与靛红衍生的酮亚胺的有机催化非对映和对映选择性 [3 + 2] 环加成反应。与成熟的路易斯酸活化方案通过与受体基团配位来促进D-A环丙烷的反应性不同，在该反应中，二氰基环丙基甲基酮可以通过使用二氢奎宁衍生的方酰胺作为布朗斯台德碱对供体基团进行亲核活化来活化催化剂。该反应以 83-99% 的产率提供具有两个不相邻的四取代和三取代立体中心的官能化螺[oxindole-3,2'-吡咯烷]，具有中等至优异的非对映选择性（高达 >20:1 非对映异构体比率 (dr)），在温和条件下具有出色的对映选择性（高达 >99% 对映体过量 (ee)）。

更新日期：2024-06-10

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