- In-situ-generation of alkylsilyl peroxides from alkyl hydroperoxides and their subsequent copper-catalyzed functionalization with organosilicon compounds
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Alkylsilyl peroxides were generated in situ from the corresponding alkyl hydroperoxides using organosilicon compounds of the type Me3SiX (X = CN, N3, and halogens) and an amine base. Subsequent in situ copper-catalyzed homolytic cleavage of the alkylsilyl peroxides afforded alkyl radicals, which were then trapped with X (X = CN, N3, and halogens) to furnish products with new carbon-carbon, carbon-nitrogen, or carbon-halogen bonds in good to high yields.
- Xu, Weiping,Zhong, Wenfeng,Yang, Qin,Kato, Terumasa,Liu, Yan,Maruoka, Keiji
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- Copper-catalyzed radical ring-opening halogenation with HX
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An efficient copper-catalyzed radical ring-opening halogenation with HX (aq) is described. This protocol features redox-neutral conditions, green halogen sources, and a broad substrate scope, providing practical access to distally chlorinated, brominated and iodinated alkyl ketones and alkyl nitriles with moderate to good yields. This journal is
- Bai, Ming,Duan, Xin-Hua,Guo, Li-Na,Liu, Shuai,Sun, Qing-Xin,Xu, Peng-Fei
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p. 8652 - 8655
(2021/09/04)
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- Far-end halogenated alkyl ketone taking HX as halogen source and synthesis method of far-end halogenated alkyl ketone
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The invention relates to a far-end halogenated alkyl ketone taking HX as a halogen source and a synthesis method of the far-end halogenated alkyl ketone. The method comprises the following steps that: cycloalkyl peroxy alcohol and a copper acetate catalyst are added in a nitrogen atmosphere, then HCl, HBr and an HI solution are added as halogens, and stirring is carried out at normal temperature; after a reaction is finished, sufficient water is added to extract a reaction solvent N-methyl pyrrolidone, performing washing with saturated saline solution, an organic phase is dried with anhydrous sodium sulfate, the organic phase is concentrated under reduced pressure, so that the solvent can be removed; and column chromatography is performed on the organic phase to obtain a target product. According to the far-end halogenated alkyl ketone taking the HX as the halogen source and the synthesis method of the far-end halogenated alkyl ketoneinvention, industrial bulk raw materials HCl, HBr and an HI solution are used as the halogen source, free radical halogenation of C-C bond cracking is realized, and the far-end halogenated alkyl alkyl ketone compound is obtained with high yield; the byproduct of the reaction is water, so that the environmental pollution is reduced, and the industrial production benefit is greatly improved.
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Paragraph 0032
(2021/08/21)
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- Ring-opening iodination and bromination of unstrained cycloalkanols through ?-scission of alkoxy radicals
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Ring-opening iodination or bromination of unstrained cycloalkanols with NaI or NaBr and PhI(OAc)2 under visible light irradiation is developed. In this protocol the concentration of I2is modulated through the generation of triiodide (I3-), thus significantly avoiding undesired side reactions. The reaction is under mild conditions and has a wide substrate scope, thus providing a practically useful method for accessing ω-iodo or ω-bromoketones.
- Shi, Jiang-Ling,Wang, Yuankai,Wang, Zixuan,Dou, Bowen,Wang, Jianbo
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supporting information
p. 5002 - 5005
(2020/05/18)
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- Visible-light-enhanced ring opening of cycloalkanols enabled by br?nsted base-tethered acyloxy radical induced hydrogen atom transfer-electron transfer
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A metal-free ring opening/halogenation of cycloalkanols, which combines both PPO/TBAX oxidant system and blue LEDs irradiation, is presented. This method produces diverse γ, α, and even more remotely halogenated ketones in moderate to excellent yields under mild conditions. Interestingly, experimental and computational studies demonstrate the novel ring size-dependent concerted/stepwise (four-/five- to eight-membered rings) hydrogen atom transfer-electron transfer induced by Br?nsted base-tethered acyloxy radical, which indicates distinct advantages brought by the cyclic structure of diacyl peroxides.
- Zhao, Rong,Yao, Yuan,Zhu, Dan,Chang, Denghu,Liu, Yang,Shi, Lei
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supporting information
p. 1228 - 1231
(2018/02/23)
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- Photolysis of 1-alkylcycloalkanols in the presence of (diacetoxyiodo) benzene and I2. Intramolecular selectivity in the β-scission reactions of the intermediate 1-alkylcycloalkoxyl radicals
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The C-C β-scission reactions of 1-alkylcycloalkoxyl radicals, generated photochemically by visible light irradiation of CH2Cl 2 solutions containing the parent 1-alkylcycloalkanols, (diacetoxy)-iodobenzene (DIB), and I2, have been investigated through the analysis of the reaction products. The 1-alkylcycloalkoxyl radicals undergo competition between ring opening and C-alkyl bond cleavage as a function of ring size and of the nature of the alkyl substituent. With the 1-propylcycloheptoxyl, 1-propylcyclooctoxyl, and 1-phenylcyclooctoxyl radicals, formation of products deriving from an intramolecular 1,5-hydrogen atom abstraction reaction from the cycloalkane ring has also been observed. The results are discussed in terms of release of ring strain associated to ring opening, stability of the alkyl radical formed by C-alkyl cleavage, and with cycloheptoxyl and cyclooctoxyl radicals, also in terms of the possibility of achieving a favorable geometry for intramolecular hydrogen atom abstraction.
- Antunes, Carla S. Aureliano,Bietti, Massimo,Lanzalunga, Osvaldo,Salamone, Michela
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p. 5281 - 5289
(2007/10/03)
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