对4-羟基香豆素与(E)-3-芳基-2-硝基丙-2-烯醇的反应有显着的溶剂作用:轻松合成高度取代的呋喃/吡喃并[3,2- c ]苯二甲基†
摘要:
在水和DMSO介质中,已观察到对4-羟基香豆素衍生物与(E)-3-芳基/杂芳基-2-硝基丙-2-烯醇的反应具有显着的溶剂作用。该结果用于新型官能化的呋喃/吡喃并[3,2- c ]色烯的直接合成,产率为63-93%,非对映异构体比例最高为≤99:1。此外,该方法简单,温和,高效且无催化剂一锅法可能会为香豆素核上的呋喃/吡喃环的成环提供另一种合成策略。此外,水对该反应的速率和选择性(产物)显示出显着的积极作用。
Organocatalytic Cascade Reactions: Towards the Diversification of Hydroisochromenes and Chromenes through Two Different Activation Modes
作者:David Cruz Cruz、Rasmus Mose、Clarisa Villegas Gómez、Stine V. Torbensen、Martin S. Larsen、Karl Anker Jørgensen
DOI:10.1002/chem.201403505
日期:2014.9.1
The organocatalytic enantioselective syntheses of functionalized hydroisochromenes and chromenes by trienamine‐mediated [4+2]‐cycloaddition/nucleophilic ring‐closing and iminium‐ion/aminal‐mediated oxa‐Michael/Michael/nucleophilic ring‐closing with 2‐nitroallylic alcohols are presented. The corresponding cycloadducts, with up to five stereocenters, are formed in good yield and excellent enantioselectivities
介绍了由三烯胺介导的[4 + 2]-环加成/亲核开环和亚胺离子/氨基介导的氧杂-Michael / Michael /亲核与2-硝基烯丙醇成环的功能化氢异色酮和色烯的有机催化对映选择性合成。 。形成具有最多五个立体中心的相应的环加合物,具有良好的产率和优异的对映选择性。已经证明了所得产物的合成应用。
An Organocatalytic Asymmetric Tandem Reaction for the Construction of Bicyclic Skeletons
作者:Chun-Li Cao、You-Yun Zhou、Jian Zhou、Xiu-Li Sun、Yong Tang、Yu-Xue Li、Guang-Yu Li、Jie Sun
DOI:10.1002/chem.200900696
日期:2009.10.26
the presence of catalytic pyrrolidine‐thiourea, which affords bicyclicskeletons with four or five stereocenters in one single reaction with up to 98 % ee in moderate to high yields. The cooperative effects of both enamine and the Brønsted acid are found to be crucial for the high reactivity and enantioselectivity of this cascade reaction, which is demonstrated by both theoretical calculation and experimental