Synthesis of Spirooxindole-1,2-oxazinan-5-ones through 2,2,2-Trifluoroethanol Promoted [3 + 3] Cycloaddition of <i>N</i>-Vinyl Oxindole Nitrones and Oxyallyl Cations
作者:Hao Yuan、Yu-Zheng Wu、Yu-Han Fang、Chun-Hua Chen、Cui Liang、Dong-Liang Mo
DOI:10.1021/acs.joc.3c01477
日期:2023.12.1
2-trifluoroethanol (TFE)-promoted [3 + 3] cycloaddition of N-vinyl oxindole nitrones with oxyallyl cations generated from α-tosyloxy ketones under mild reaction conditions. Mechanistic studies revealed that [3 + 3] cycloaddition might involve two possible reaction pathways, including direct [3 + 3] cycloaddition of N-vinyl oxindole ntirones with oxyallyl cations, or the addition of TFE to N-vinyl oxindole
通过 2,2,2-三氟乙醇 (TFE) 促进的N-乙烯基羟吲哚硝酮与氧烯丙基阳离子的 [3 + 3] 环加成反应,以中等至优异的产率制备了多种螺吲哚-1,2-恶嗪南-5-酮衍生物由α-甲苯磺酰氧基酮在温和的反应条件下生成。机理研究表明,[3+3]环加成可能涉及两种可能的反应途径,包括N-乙烯基羟吲哚硝酮与氧烯丙基阳离子的直接[3+3]环加成,或TFE加成到N-乙烯基羟吲哚硝酮上,顺序加成到N-乙烯基羟吲哚硝酮上。氧烯丙基阳离子、消除和环化。该方法具有反应条件温和、底物范围广、官能团耐受性好、易于克级放大制备以及TFE新应用等特点。