Selective C3-Allylation and Formal [3 + 2]-Annulation of Spiro-Aziridine Oxindoles: Synthesis of 5′-Substituted Spiro[pyrrolidine-3,3′-oxindoles] and Coerulescine
作者:SK Abu Saleh、Atanu Hazra、Maya Shankar Singh、Saumen Hajra
DOI:10.1021/acs.joc.2c00863
日期:2022.7.1
selective C3-allylation and formal [3 + 2]-annulation of spiro-aziridine oxindoles with allylsilanes have been demonstrated to deliver direct access to 3-allyl-3-aminomethyl oxindoles and 5-silyl methyl spiro[pyrrolidine-3,3′-oxindoles], respectively. The acid-catalyzed methods do not provide any stereoselectivity when chiral spiroaziridines are used. However, the reaction of nonracemic sprioaziridines with
布朗斯台德酸和/或路易斯酸催化的选择性 C3 烯丙基化和形式 [3 + 2] 环化螺环氮丙啶羟吲哚与烯丙基硅烷已被证明可直接获得 3-烯丙基-3-氨基甲基羟吲哚和 5-甲硅烷基甲基螺[吡咯烷-3,3'-羟吲哚],分别。当使用手性螺氮丙啶时,酸催化方法不提供任何立体选择性。然而,非外消旋螺氮丙啶与烯丙基-格氏试剂在无催化剂条件下的反应提供了具有良好立体选择性(ee 高达 80%)的 3-烯丙基-3-氨基甲基羟吲哚。烯丙基化方案用于短期合成 coerulescine 和各种 5'-取代螺 [pyrrolidine-3,3'-oxindoles]。