Enantioselective synthesis of spiro[4<i>H</i>-pyran-3,3′-oxindole] derivatives catalyzed by cinchona alkaloid thioureas: Significant water effects on the enantioselectivity
作者:Swapna Konda、Satish Jakkampudi、Hadi D. Arman、John C.-G. Zhao
DOI:10.1080/00397911.2019.1651866
日期:——
Abstract An efficient stereoselective three-component reaction for the synthesis of functionalized spiro[4H-pyran-3,3′-oxindole] derivatives was realized through an organocatalyzed domino Knoevenagel/Michael/cyclization reaction using a cinchonidine-derived thiourea as the catalyst. Using water as the additive was found to improve the product ee values significantly. Under the optimized conditions
摘要 以辛可尼丁衍生的硫脲为催化剂,通过有机催化的多米诺克诺韦纳格尔/迈克尔/环化反应,实现了一种有效的立体选择性三组分反应,用于合成功能化螺[4H-吡喃-3,3'-羟吲哚]衍生物。发现使用水作为添加剂可以显着提高产品ee值。在优化的条件下,靛红、丙二腈和 1,3-二羰基化合物之间的反应以良好的产率 (71–92%) 和中到高的 ee 值 (高达 87% ee) 产生所需的螺吲哚产物。图形概要