Synthesis of Diels–Alder adducts of N-arylmaleimides by a multicomponent reaction between maleic anhydride, dienes, and anilines
作者:J. Alberto Guevara-Salazar、Delia Quintana-Zavala、Hugo A. Jiménez-Vázquez、José Trujillo-Ferrara
DOI:10.1007/s00706-011-0515-5
日期:2011.8
AbstractWe have carried out the synthesis and characterization of some hexahydroisoindolyl benzoic acids and their corresponding ethyl esters by a multicomponent reaction (MCR) between aminobenzoic acids or aminobenzoates, maleicanhydride, and isoprene in the absence of catalysts. According to additional experiments, the MCR takes place by sequential formation of N-arylmaleamic acids from the aminobenzoic
摘要我们在不存在催化剂的情况下,通过氨基苯甲酸或氨基苯甲酸酯,马来酸酐和异戊二烯之间的多组分反应(MCR),对一些六氢异吲哚基苯甲酸及其相应的乙酯进行了合成和表征。根据其他实验,MCR是通过依次从氨基苯甲酸或氨基苯甲酸酯和顺丁烯二酸酐,酸和异戊二烯的Diels–Alder加合物,最后是酰亚胺形成N-芳基马来酰胺酸而发生的。加合物的1 H NMR数据(耦合常数)表明,相应的环己烯环的优选构型是顺式-船,由密度泛函理论(DFT)构象分析和相应构象异构体自旋-自旋耦合常数的DFT计算所支持的事实。我们的MCR合成方法在其他加合物的合成中成功进行了测试,其中使用了环戊二烯和其他苯胺。 图形概要
Enantioselective Nickel-Catalyzed Hydrocyanative Desymmetrization of Norbornene Derivatives
nickel-catalyzed enantioselective hydrocyanation of N-aryl 5-norbornene-endocis-2,3-dicarboximides was reported. This desymmetrization process allows for a quick construction of both continuous stereogenic carbon centers and remote N–CAr atropisomeric chirality. Mechanism studies indicated that the resident carbonyl group of the substrates plays a key role in the enantioselectivity.
Catalytic Diastereospecific and Enantioselective (3 + 2) Transannulations of 1,2,3-Thiadiazoles with Strained Norbornene Derivatives
作者:Cunzhi Chen、Shuyan Fang、Ziyang Dong、Jiaxi Xu、Zhanhui Yang
DOI:10.1021/acs.orglett.2c00330
日期:2022.3.25
ring-strain-release strategy, iridium-catalyzed transannulations with norbornene derivatives are achieved in a diastereospecific and enantioselective manner. The first asymmetric transannulations of 1,2,3-thiadiazoles are reported.
In order to understand the vital role of the imide substituent, a systematic theoretical DFT study at the PCM/B3LYP/6-31+G(d) level was carried out. We found that substituents at the nitrogen atom of epoxyimides exerted remarkable effects on the regioselectivity in the ethanolysis reaction, based on the solvent effects and intramolecular electronic interactions. Particularly, the preference for the
Under mechanochemical milling conditions, Diels-Alder cycloaddition of cyclopentadiene with maleic anhydride and maleimide derivatives proceeded very smoothly, affording endo-norbornenes exclusively in quantitative yield. All the transformations were accomplished at room temperature without using any catalyst or organic solvent, thus the workup and purification procedure is very simple. Control experiments on traditional and other tentative conditions were also investigated.