- Regio- and Stereoselective Cascade of β,γ-Unsaturated Ketones by Dipeptided Phosphonium Salt Catalysis: Stereospecific Construction of Dihydrofuro-Fused [2,3-b] Skeletons
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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.
- Chen, Yayun,He, Jiajia,Jiang, Chunhui,Ren, Xiaoyu,Su, Zhishan,Wang, Tianli,Xiao, Kai,Zhang, Hongkui,Zhuang, Cheng
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supporting information
p. 19860 - 19870
(2021/08/06)
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- Asymmetric dearomatization of 2-nitrobenzofurans by organocatalyzed one-step Michael addition to access 3,3′-disubstituted oxindoles
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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.
- Ge, Zhen-Zhen,Wang, Zhen-Hua,Xie, Ke-Xin,Yang, Lei,You, Yong,Yuan, Wei-Cheng,Zhao, Jian-Qiang,Zhou, Ming-Qiang
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supporting information
p. 2586 - 2589
(2020/03/10)
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- Facile synthesis of chiral [2,3]-fused hydrobenzofuran: Via asymmetric Cu(i)-catalyzed dearomative 1,3-dipolar cycloaddition
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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.
- Liang, Lei,Niu, Hong-Ying,Wang, Dong-Chao,Yang, Xin-He,Qu, Gui-Rong,Guo, Hai-Ming
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supporting information
p. 553 - 556
(2019/01/10)
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- Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans
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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.
- Cheng, Qiang,Zhang, Hui-Jun,Yue, Wen-Jun,You, Shu-Li
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supporting information
p. 428 - 436
(2017/09/22)
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- A new efficient method for the total synthesis of linear furocoumarins
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A new efficient method for the synthesis of linear furocoumarins by a Nef reaction and intramolecular cyclocondensation in one pot results in the construction of a benzofuran ring. This method provides a new strategy to furnish the benzofuran framework easily, and also allows the convenient synthesis of furocoumarin derivatives with different substituents on the coumarin ring by a subsequent Pechmann reaction. This strategy has also been applied to the preparation of four additional benzofuran derivatives. Georg Thieme Verlag Stuttgart.
- Zhang, Bang-Le,Wang, Fang-Dao,Yue, Jian-Min
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p. 567 - 570
(2007/10/03)
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