A Convenient Synthesis of Substituted 1-Bromo-1-nitroalkenes
作者:Yanchang Shen、Baozhen Yang
DOI:10.1080/00397919308020394
日期:1993.1
Abstract The reaction of aldehydes with bromonitromethane in the presence of tri-n-butylarsine affording substituted 1-bromo-1-nitroalkenes in good yields is described.
Highly regio- and diastereoselective [3 + 2]-cycloadditions involving indolediones and α,β-disubstituted nitroethylenes
作者:Madhuri P. Rao、Shubha S. Gunaga、Johannes Zuegg、Rambabu Pamarthi、Madhu Ganesh
DOI:10.1039/c9ob01429b
日期:——
A highlydiastereoselective [3 + 2]-cycloaddition strategy involving multiple oxindoles and several α,β-disubstituted nitroethylenes is developed to access tetra-substituted α-spiropyrrolidine frameworks. A variety of α-amino acids were employed for the first time in order to generate azomethine ylides under thermal conditions, affording regioisomers 13 and 14 merely by changing the α-substituents
Asymmetricorganocatalyticdomino type Michael-SN2 reactions give access to enantiomerically enriched dihydrofuran derivatives that can be used as valuable chiral building blocks. A variety of α-bromonitroalkenes and 1,3-dicarbonyl compounds were allowed to react under optimized conditions, in the presence of a bifunctional quinine-derived sterically encumbered squaramide (H-bond donor) organocatalyst
不对称有机催化多米诺骨牌型 Michael-S N 2 反应提供了对映异构富集的二氢呋喃衍生物,可用作有价值的手性构件。在双功能奎宁衍生的空间位阻方酸酰胺(H 键供体)有机催化剂的存在下,允许各种 α-溴硝基烯烃和 1,3-二羰基化合物在优化条件下反应。本文中开发的条件在反应持续时间(1-6 小时vs. 24-96 小时)和反应温度(室温vs. -20 °C 至 -50 °C )方面优于文献中已知的方法) 产生具有高达 97% ee 的良好对映选择性的非对映选择性产物。
Asymmetric Synthesis of Dihydrofurans via Organocatalytic Domino Michael-Alkylation Reaction
organocatalyst to catalyze the asymmetric domino Michael–alkylation reaction between cyclohexane‐1,3‐dione derivatives and bromonitrostyrenes. For dimedone, the corresponding bicyclic 2,3‐dihydrofurans with two stereocenters were obtained in up to 99 % yield with 95:5 d.r. and 96 % ee. For prochiral 5‐monosubstituted cyclohexane‐1,3‐diones, the desymmetrization reaction provided the bicyclic 2,3‐dihydrofurans
Mild and efficient synthesis of <i>trans</i>-3-aryl-2-nitro-2,3-dihydrobenzofurans on water
作者:Juhua Feng、Siyuan Wang、Jinxiang Feng、Qiuju Li、Junping Yue、Guizhou Yue、Ping Zou、Guangtu Wang
DOI:10.1039/d0nj00548g
日期:——
An environmental-friendly and mild method has been successfully developed for the synthesis of 3-aryl-2-nitro-2,3-dihydrobenzofurans through domino Friedel–Crafts/substitution reaction of (Z)-bromonitrostyrenes with sesamol. A variety of substrates performed well in this reaction, and the corresponding 3-aryl-2-nitro-2,3-dihydrobenzofurans were obtained in excellent yields (up to 99%). Significantly