Organocatalytic Enantioselective Tandem Michael Addition and Cyclization Reaction of Trisubstituted 2-Nitro-1,3-enynes with Cyclic 1,3-Diketones
作者:Zi-Min Xing、Le-Le Song、Feng-Xing Li、Nian-Sheng Xu、Lu-Feng Wang、Zi-Fa Shi、Xiao-Ping Cao
DOI:10.1002/adsc.201700085
日期:2017.6.6
An enantioselective tandem Michael addition/cyclization reaction between trisubstituted 2‐nitro‐1,3‐enynes and cyclic 1,3‐diketones catalyzed by a chiral organosquaramide catalyst in the presence of Ag2CO3 was developed. The chiral functionalized chromene products could be obtained in good yield and in 80–99% enantiomeric excess. The structures and absolute configurations of some of the products were
在Ag 2 CO 3存在下,通过手性有机方酰胺催化剂催化三取代的2-硝基-1,3-烯炔与环状的1,3-二酮之间的对映选择性串联迈克尔加成/环化反应。手性官能化的色烯产品可以以良好的收率和80-99%的对映异构体过量获得。X射线晶体学分析证实了某些产品的结构和绝对构型。
Chiral<i>N</i>,<i>N</i>′-Dioxide-Organocatalyzed Regio-, Diastereo- and Enantioselective Michael Addition-Alkylation Reaction
A highly regio‐, diastereo‐ and enantioselectiveMichaeladdition–alkylationreaction between α‐substituted cyano ketones and (Z)‐bromonitrostyrenes has been realized by using a chiral N,N′‐dioxide as organocatalyst. A variety of substrates performed well in this reaction, and the corresponding multifunctionalized chiral 2,3‐dihydrofurans were obtained in up to 95 % yield with 95:5 dr and 93 % ee.
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