Sequential 1,3-Dipolar Cycloaddition of Nitrones to β-(2-Aminophenyl) α,β-Ynones and Cyclocondensation: A New Entry to the Isoxazolino[4,5-c]quinoline Ring
4-Dimethylaminopyridine-Mediated [3+3] Cycloaddition of Aza-oxyallyl Cations and Nitrones
作者:Qianfa Jia、Dongli Li、Ming Lang、Kun Zhang、Jian Wang
DOI:10.1002/adsc.201700415
日期:2017.11.10
A new 4‐dimethylaminopyridine (DMAP)‐mediated [3+3] cycloaddition reaction of in situ‐ generated aza‐oxyallylcations with nitrones is reported. This simple and efficient method delivers a series of new motifs in good to excellent yields under mild conditions.
Diastereoselective Synthesis of Chromeno[3,2-<i>d</i>]isoxazoles via Brønsted Acid Catalyzed Tandem 1,6-Addition/Double Annulations of <i>o</i>-Hydroxyl Propargylic Alcohols
作者:Zhu Li、Pei-Xu Zhang、Zhao-Zhao Li、Xing-Lu Zhang、Hong-Yuan Cao、Yu-Ning Gao、Ming Bian、Hui-Yu Chen、Zhen-Jiang Liu
DOI:10.1021/acs.orglett.2c02830
日期:2022.9.23
A Brønsted acid catalyzed tandem process to access densely functionalized chromeno[3,2-d]isoxazoles with good to excellent yields and diastereoselectivities was disclosed. The procedure is proposed to involve a 1,6-conjugate addition/electrophilic addition/double annulations process of alkynyl o-quinone methides (o-AQMs) in situ generated from o-hydroxyl propargylic alcohols with nitrones. Mild conditions
公开了一种布朗斯台德酸催化的串联工艺,用于获得致密官能化的铬烯基 [3,2- d ] 异恶唑,具有良好至优异的产率和非对映选择性。该程序拟涉及 1,6-共轭加成/亲电加成/双环化炔基邻苯二酚甲基化物 (o -AQMs) 的过程,原位由邻羟基炔丙醇和硝酮生成。温和的条件、良好的官能团相容性、易于放大反应和进一步的产品转化展示了其潜在的应用。
A torquoselective extrusion of isoxazoline N-oxides. Application to the synthesis of aryl vinyl and divinyl ketones for Nazarov cyclization
作者:Daniel P. Canterbury、Ildiko R. Herrick、Joann Um、K.N. Houk、Alison J. Frontier
DOI:10.1016/j.tet.2008.10.003
日期:2009.4
A mild, convenient reaction sequence for the synthesis of Nazarov cyclization substrates is described, The [3+2] dipolar cycloaddition of a nitrone and an electron-deficient alkyne gives all isolable isoxazoline intermediate, which upon oxidation undergoes stereoselectivc extrusion of nitrosomethane to give aryl vinyl or divinyl ketones. (C) 2008 Elsevier Ltd. All right, reserved.
Enantioselective Addition of Nitrones to Activated Cyclopropanes
作者:Mukund P. Sibi、Zhihua Ma、Craig P. Jasperse
DOI:10.1021/ja0421497
日期:2005.4.1
In this paper, we demonstrate the first examples of chiral Lewis acid catalysis in the formation of tetrahydro-1,2-oxazines with very high enantioselectivity starting with diactivated cyclopropanes and nitrones (>90% yields and ee). Reactions with racemic substituted cyclopropanes provide approximately 1:1 diastereomeric tetrahydro-1,2-oxazine products with high enantioselectivity. Mechanistic information for the formation of the tetrahydro-1,2-oxazines is also detailed.