phosphine-catalyzed asymmetric dearomative [3+2] cycloaddition of 2-nitrobenzofurans with aldehyde-derived Morita–Baylis–Hillman (MBH) carbonates or allenoate was developed. The reaction with MBH carbonates resulted in a series of cyclopentabenzofurans containing three contiguous stereocenters with good to high yields, diastereoselectivities and enantioselectivities. The use of allenoate also gave the target product
Regio‐ and Stereoselective Cascade of β,γ‐Unsaturated Ketones by Dipeptided Phosphonium Salt Catalysis: Stereospecific Construction of Dihydrofuro‐Fused [2,3‐b] Skeletons
作者:Hongkui Zhang、Jiajia He、Yayun Chen、Cheng Zhuang、Chunhui Jiang、Kai Xiao、Zhishan Su、Xiaoyu Ren、Tianli Wang
DOI:10.1002/anie.202106046
日期:2021.9
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 Brønstedacid moieties
Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans
作者:Qiang Cheng、Hui-Jun Zhang、Wen-Jun Yue、Shu-Li You
DOI:10.1016/j.chempr.2017.06.015
日期:2017.9
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
Metal-Free Diastereo- and Enantioselective Dearomative Formal [3 + 2] Cycloaddition of 2-Nitrobenzofurans and Isocyanoacetate Esters
作者:Adrian Laviós、Amparo Sanz-Marco、Carlos Vila、M. Carmen Muñoz、José R. Pedro、Gonzalo Blay
DOI:10.1021/acs.orglett.2c00427
日期:2022.3.25
The diastereo- and enantioselective dearomative formal [3 + 2] cycloaddition of 2-nitrobenzofurans and α-aryl-α-isocyanoacetate esters provides tricyclic compounds bearing the 3a,8b-dihydro-1H-benzofuro[2,3-c]pyrrole framework with three consecutive stereogenic centers. The reaction was enabled by a cupreine-ether organocatalyst. The reaction products were obtained with almost full diastereoselectivity
2-硝基苯并呋喃和α-芳基-α-异氰基乙酸酯的非对映和对映选择性脱芳香形式[3 + 2]环加成得到带有3 a ,8 b -二氢-1 H -苯并呋喃[2,3- c ]的三环化合物具有三个连续立体中心的吡咯框架。该反应是通过铜醚有机催化剂实现的。获得的反应产物具有几乎完全的非对映选择性,并且对于许多取代的2-硝基苯并呋喃和异氰乙酸酯具有优异的对映体过量。
Asymmetric dearomatization of 2-nitrobenzofurans by organocatalyzed one-step Michael addition to access 3,3′-disubstituted oxindoles
An efficient enantioselective dearomatization of 2-nitrobenzofurans was realized by organocatalyzed one-step Michael addition to access structurally diverse 3,3′-disubstituted oxindoles.