30335-67-2Relevant academic research and scientific papers
An Improved Synthesis of 2-Nitrobenzofurans
Tromelin, Anne,Demerseman, Pierre,Royer, Rene
, p. 1074 - 1076 (1985)
2-Nitrobenzofurans 4 are prepared in improved yields by reacting o-hydroxybenzaldehydes 1 and bromonitromethane (2) at low temperature in order to avoid the dehydration of the aldol intermediate 3 in the alkaline condensation medium.This aldol 3 is then quantitatively dehydrated by heating in acetic anhydride.
Regio- and Stereoselective Cascade of β,γ-Unsaturated Ketones by Dipeptided Phosphonium Salt Catalysis: Stereospecific Construction of Dihydrofuro-Fused [2,3-b] Skeletons
Chen, Yayun,He, Jiajia,Jiang, Chunhui,Ren, Xiaoyu,Su, Zhishan,Wang, Tianli,Xiao, Kai,Zhang, Hongkui,Zhuang, Cheng
, p. 19860 - 19870 (2021/08/06)
Chiral (dihydro)furo-fused heterocycles are significant structural motifs in numerous natural products, functional materials and pharmaceuticals. Therefore, developing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein, we develop an effective, modular method by a dipeptide-phosphonium salt-catalyzed regio- and stereoselective cascade reaction of readily available linear β,γ-unsaturated ketones with aromatic alkenes, affording a wide variety of structurally fused heterocyclic molecules in high yields with excellent stereoselectivities. Moreover, mechanistic investigations revealed that the bifunctional phosphonium salt controlled the regio- and stereoselectivities of this cascade reaction, particularly proceeding through the initial ketone α-addition followed by O-participated substitution; and the multiple hydrogen-bonding interactions between Br?nsted acid moieties of catalyst and nitro group of aromatic alkene were crucial in asymmetric induction. Given the generality, versatility, and high efficiency of this method, we anticipate that it will have broad synthetic utilities.
Asymmetric dearomatization of 2-nitrobenzofurans by organocatalyzed one-step Michael addition to access 3,3′-disubstituted oxindoles
Ge, Zhen-Zhen,Wang, Zhen-Hua,Xie, Ke-Xin,Yang, Lei,You, Yong,Yuan, Wei-Cheng,Zhao, Jian-Qiang,Zhou, Ming-Qiang
, p. 2586 - 2589 (2020/03/10)
An efficient enantioselective dearomatization of 2-nitrobenzofurans was realized via an organocatalyzed one-step Michael addition process. This method provides a facile strategy to access a range of structurally diverse 3,3′-disubstituted oxindoles, which feature an intriguing combination of two privileged motifs including 3-pyrrolyl-substituted-oxindoles and 2,3-dihydrobenzofurans substructures, in excellent results.
Phosphine-Catalyzed Enantioselective Dearomative [3+2]-Cycloaddition of 3-Nitroindoles and 2-Nitrobenzofurans
Wang, Huamin,Zhang, Junyou,Tu, Youshao,Zhang, Junliang
, p. 5422 - 5426 (2019/03/17)
Over the past years, the metal-catalyzed dearomative cycloaddition of 3-nitroindoles and 2-nitrobenzofurans have emerged as a powerful protocol to construct chiral fused heterocyclic rings. However, organocatalytic dearomative reaction of these two classe
Facile synthesis of chiral [2,3]-fused hydrobenzofuran: Via asymmetric Cu(i)-catalyzed dearomative 1,3-dipolar cycloaddition
Liang, Lei,Niu, Hong-Ying,Wang, Dong-Chao,Yang, Xin-He,Qu, Gui-Rong,Guo, Hai-Ming
, p. 553 - 556 (2019/01/10)
Intermolecular asymmetric dearomative 1,3-dipolar cycloaddition of 2-nitrobenzofurans with azomethine ylides was enabled by using a chiral Cu(i)/(S,Sp)-iPr-Phosferrox catalyst. As a result, a series of highly stereoselective chiral [2,3]-fused hydrobenzofurans possessing four contiguous stereogenic centers were obtained with good to high yields, diastereoselectivities and enantioselectivities. The reaction has broad substrate scope tolerating various functional groups.
Palladium(0)-Catalyzed Dearomatization of 2-Nitrobenzofurans through Formal (3+2) Cycloadditions with Vinylcyclopropanes: A Straightforward Access to Cyclopenta[ b ]benzofurans
Ling, Johanne,Laugeois, Maxime,Michelet, Véronique,Ratovelomanana-Vidal, Virginie,Vitale, Maxime R.
supporting information, p. 928 - 932 (2018/02/14)
In the context of the palladium-catalyzed dearomatization of electron-poor arenes, we report herein that various 2-nitrobenzofurans efficiently undergo a dearomative (3+2) cycloaddition with vinylcyclopropanes. This new method gives access to a wide variety of cyclo-penta[ b ]benzofuran derivatives in a straightforward manner.
Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans
Cheng, Qiang,Zhang, Hui-Jun,Yue, Wen-Jun,You, Shu-Li
, p. 428 - 436 (2017/09/22)
Stereoselective construction of highly functionalized heterocyclic molecules is an ongoing concern for the chemical community. Among the various strategies developed with this goal, catalytic asymmetric dearomatization, an attractive method for constucting cyclic molecules with multiple stereocenters from readily available aromatic compounds, has received extensive attention in recent years. Here, we report a highly stereoselective construction of tetrahydrofurobenzofurans and tetrahydrofurobenzothiophenes via palladium-catalyzed dearomative [3 + 2] cycloaddition of nitrobenzofurans and nitrobenzothiophenes, respectively. Good to excellent yields (63%–92%), diastereoselectivity (13/1 → >20/1 dr), and enantioselectivity (75%–95% ee) were obtained, leading to products with vicinal stereogenic carbon centers. The reaction features wide substrate scope and diverse transformations of the products.
Potassium trinitromethanide as a 1,1-ambiphilic synthon equivalent: Access to 2-nitroarenofurans
Osyanin, Vitaly A.,Osipov, Dmitry V.,Demidov, Maxim R.,Klimochkin, Yuri N.
, p. 1192 - 1198 (2014/03/21)
The first example of the use of potassium trinitromethanide as a 1,1-ambiphilic synthon equivalent for the construction of a benzofuran moiety mediated by triethylamine has been developed. The method tolerates a variety of functional groups on the starting quaternary ammonium salt and has been successfully extended to polysubstituted benzofurans. Formation of an o-quinone methide intermediate is postulated as a key to the mechanism of this cascade process.
Elimination of 3-Hydroxy-2-nitro-2,3-dihydrobenzofurans to 2-Nitrobenzofurans
Ohishi, Yoshitaka,Doi, Yoshio,Nakanishi, Teruo
, p. 1336 - 1342 (2007/10/02)
β-Elimination of stereoisomeric cis- and trans-3-hydroxy-2-nitro-2,3-dihydrobenzofurans was investigated.The 2,3-dihydrobenzofurans were stable under acidic conditions but were easily dehydrated under basic conditions to afford the corresponding 2-nitrobenzofurans.An (E1cB)R mechanism is proposed on the basis of several lines of evidence obtained from studies on kinetics, ultraviolet spectra, leaving group effect and deuterium isotope effect in the elimination reaction.Keywords- 3-hydroxy-2-nitro-2,3-dihydrobenzofuran derivative; elimination; (E1cB)R mechanism; kinetic study; carbanion intermediate; leaving group effect; isotope effect;
A TYPICAL ElcB PROCESS IN THE ELIMINATION OF 3-HYDROXY-2-NITRO-2,3-DIHYDROBENZOFURANS TO 2-NITROBENZOFURANS
Ohishi, Yoshitaka,Doi, Yoshio,Nakanishi, Teruo
, p. 2598 - 2601 (2007/10/02)
It was clarified that the elimination of the 3-hydroxy-2-nitro-2,3-dihydrobenzofurans proceeded via a typical(ElcB)R mechanism in the presence of KOH to give the 2-nitrobenzofurans.
