- Stereodivergent Synthesis of Tetrahydrofuroindoles through Pd-Catalyzed Asymmetric Dearomative Formal [3+2] Cycloaddition
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A stereodivergent synthesis of tetrahydrofuroindoles through palladium-catalyzed asymmetric dearomative formal [3+2] cycloaddition of nitroindoles with epoxybutenes was developed. The polarity of the solvent was found to play a key role in the diastereoselectivity. In toluene, good to excellent yields (70–99 %), diastereoselectivity (87/13->95/5 d.r.), and enantioselectivity (85/15–94/6 e.r.) were obtained, regardless of the properties of the substituents on nitroindoles. In acetonitrile, tetrahydrofuroindoles of a different diastereoisomer were produced with good to excellent yields (75–98 %) and stereoselectivity (78/22–93/7 d.r., 93/7–99/1 e.r.). Mechanistic studies were conducted to illustrate the origin of the diastereodivergency. The kinetic experiments indicate that the rate-determining step of this reaction is different in different solvents. ESI-MS experiments also support the existence of key palladium complex intermediates and the catalytic cycle of the reaction.
- Cheng, Qiang,Zhang, Fang,Cai, Yue,Guo, Yin-Long,You, Shu-Li
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- Silver-Catalyzed Asymmetric Dearomatization of Electron-Deficient Heteroarenes via Interrupted Barton–Zard Reaction
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Herein we report a catalytic asymmetric dearomatization reaction of electron-deficient heteroarenes with α-substituted isocyanoacetates through an interrupted Barton–Zard reaction. A range of optically active pyrrolo[3,4-b]indole derivatives was obtained
- Wan, Qian,Xie, Jia-Hao,You, Shu-Li,Yuan, Yao-Feng,Zheng, Chao
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supporting information
p. 19730 - 19734
(2021/08/03)
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- Phosphine-Catalyzed Enantioselective Dearomative [3+2]-Cycloaddition of 3-Nitroindoles and 2-Nitrobenzofurans
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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
- Wang, Huamin,Zhang, Junyou,Tu, Youshao,Zhang, Junliang
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p. 5422 - 5426
(2019/03/17)
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- Phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles and allenoates
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The efficient phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles with allenoates has been successfully developed, providing a facile access to cyclopenta[b]indolines with good to excellent yields and high diastereoselectivities. This strategy features mild reaction conditions, high functional group tolerance, and scalability. Additionally, the 2-nitrobenzofuran and 2-nitrobenzothiophene were good dearomative [3+2] annulation partners.
- Liu, Kui,Wang, Gang,Cheng, Shao-Jie,Jiang, Wen-Feng,He, Cheng,Ye, Zhi-Shi
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p. 1885 - 1890
(2019/06/21)
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- Palladium(0)-Catalyzed Dearomative [3 + 2] Cycloaddition of 3-Nitroindoles with Vinylcyclopropanes: An Entry to Stereodefined 2,3-Fused Cyclopentannulated Indoline Derivatives
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The palladium(0)-catalyzed diastereoselective dearomative cyclopentannulation of 3-nitroindoles with vinylcyclopropanes is described. This straightforward and highly atom-economical method leads to a wide range of functionalized indolines in good yields a
- Laugeois, Maxime,Ling, Johanne,Férard, Charlène,Michelet, Véronique,Ratovelomanana-Vidal, Virginie,Vitale, Maxime R.
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supporting information
p. 2266 - 2269
(2017/05/12)
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- Enantioselective formal [4+2] cycloadditions to 3-nitroindoles by trienamine catalysis: Synthesis of chiral dihydrocarbazoles
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The first enantioselective formal [4+2] cycloadditions of 3-nitroindoles are presented. By using 3-nitroindoles in combination with an organocatalyst, chiral dihydrocarbazole scaffolds are formed in moderate to good yields (up to 87 %) and enantioselectivities (up to 97 % ee). The reaction was extended to include enantioselective [4+2] cycloadditions of 3-nitrobenzothiophene. The reaction proceeds through a [4+2] cycloaddition/elimination cascade under mild reaction conditions. Furthermore, a diastereoselective reduction of an enantioenriched cycloadduct is presented. The mechanism of the reaction is discussed based on experimental and computational studies. A formal event: Enantioselective formal [4+2] cycloadditions of 3-nitroindoles in the presence of an organocatalyst are presented. Chiral dihydrocarbazole scaffolds are formed in moderate to good yields. The reaction also proceeds with 3-nitrobenzothiophene. The mechanism of the reaction is discussed based on experimental and computational studies.
- Li, Yang,Tur, Fernando,Nielsen, Rune Pagh,Jiang, Hao,Jensen, Frank,J?rgensen, Karl Anker
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supporting information
p. 1020 - 1024
(2016/01/20)
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- Convenient synthesis of masked aminoindoles by indium mediated one-pot reductive acylation of 3- and 2-nitroindoles
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Unstable 3- and 2-aminoindoles arc generated in situ by indium mediated reduction of 3- and 2-nitroindoles and capped as the stable amides (or carbamate) in moderate to high yields under mild conditions in a one-pot procedure.
- Roy, Sujata,Gribble, Gordon W.
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- Synthesis and reactions of N-protected 3-nitroindoles
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Treatment of N-protected indoles 3 with acetyl nitrate generated in situ at low temperatures affords the corresponding 3-nitroindoles 2 in good to excellent yields. Deprotection of 1-acetyl-3-nitroindole (2h) with DBU gives 3-nitroindole (1). Reaction of
- Pelkey,Gribble
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p. 1117 - 1122
(2007/10/03)
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- One-step syntheses of the pyrrolo[3,4-b]indole and pyrrolo[2,3-b]indole ring systems from 3-nitroindoles
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The reaction of 1-ethoxycarbonyl-3-nitroindole with ethyl isocyanoacetate in the presence of DBU gives ethyl 4-ethoxycarbonyl-2,4-dihydropyrrolo[3,4-b]indole-3-carboxylate, averting a novel rearrangement that we previously reported with 3-nitro-1-phenylsu
- Pelkey, Erin T.,Gribble, Gordon W.
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p. 1873 - 1874
(2007/10/03)
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