- Copper-Catalyzed Oxidative Fragmentation of Alkynes with NFSI Provides Aryl Ketones
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A copper-catalyzed oxidative cleavage reaction of alkynes using NFSI and TBHP was described. Various terminal and internal alkyne substrates were employed to render quick access to aryl ketone products in moderate to good yields. NFSI not only functioned as N-centered radical precursors but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water in the title reactions.
- Chen, Hanfei,Cheng, Hao,Huang, Yifan,Jin, Chaochao,Song, Weihan,Tan, Chen,Tan, Jiajing,Tang, Lin,Yang, Fang,Zhang, Shuaifei
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- Synthesis of 2-Ethenylcyclopropyl Aryl Ketones via Intramolecular SN2-like Displacement of an Ester
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The efficient synthesis of trans-2-ethenylcyclopropyl aryl ketones via an intramolecular SN2-like displacement of an allylic ester is reported. A novel 1,5-acyl shift process is also observed that contributes to the product mixture. Theoretical calculations provide a rationale for the observed product ratio.
- Jung, Michael E.,Sun, Daniel L.,Dwight, Timothy A.,Yu, Peiyuan,Li, Wei,Houk
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supporting information
p. 5138 - 5141
(2016/10/14)
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- Direct oxidative installation of nitrooxy group at benzylic positions and its transformation into various functionalities
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C-H Nitrooxylation at benzylic positions has been achieved by employing the N-hydroxyphthalimide (NHPI) catalyst/cerium(IV) ammonium nitrate (CAN) reagent system. The nitrooxy groups were demonstrated to function as tentative hydroxy protecting groups, as well as excellent leaving groups for N- and C-substitution reactions. Hence, the present method offers a unique way to synthesize diverse O-, N-, or C-functionalized benzylic compounds from simple alkyl aromatics.
- Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
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supporting information; experimental part
p. 4654 - 4657
(2011/09/30)
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- Unified oxidation protocol for the synthesis of carbonyl compounds using a manganese catalyst
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We have developed a unified protocol for the oxidation of ethers, benzylic compounds, and alcohols to carbonyl compounds. The protocol uses catalytic amounts of manganese(II) chloride tetrahydrate and tri(t-butyl)-2,2':6',2Prime;- terpyridine in combination with a stoichiometric amount of either m-chloroperbenzoic acid (MCPBA) or potassium hydrogen peroxysulfate (KHSO 5). A reagent system consisting of the Mn catalyst and MCPBA permitted the chemoselective sp3 C-H oxidation of alkyl ethers and benzylic compounds to generate the corresponding ketones. Alternatively, the water-soluble inorganic salt KHSO5 in combination with the Mn catalyst was used to oxidize alcohols to ketones or carboxylic acids. Importantly, the Mn catalyst/KHSO5 system eliminates technical difficulties associated with the isolation of carboxylic acid products. All the oxidations presented in this feature article proceed at sup-ambient temperature in an aerobic atmosphere, and can therefore be used in practical syntheses of complex organic molecules. Georg Thieme Verlag Stuttgart · New York.
- Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
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experimental part
p. 2475 - 2489
(2010/09/06)
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- A simple synthetic protocol for oxidation of alkyl-arenes into ketones using a combination of HBr-H2O2
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A wide variety of alkyl- and cycloalkyl-arenes undergo benzylic C-H oxidation by employing a combination of 48% hydrogen bromide and 30% hydrogen peroxide in dichloromethane at room temperature. In addition, a chemoselective oxidation at the benzylic position is feasible by deactivating the aromatic ring using the same combination.
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.,Ghosh, Subrata
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p. 2271 - 2274
(2007/10/03)
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- Palladium-Catalyzed Reductive Coupling of Acid Chlorides with β-Stannyl Enones: Synthesis of 1,4-Diketones and Mechanistic Aspects
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The palladium-catalyzed coupling of acid chlorides with (E)-1,2-bis(tri-n-butylstannyl)ethene or β-stannyl enones gives butane-1,4-diones directly by reduction of the intermediate enedicarbonyl intermediate.The double bond conjugated with a single carbonyl group was not significantly reduced.The generality of the method is illustrated by two syntheses of the 1,4-diketone ipomeanine.By performing the reaction at lower temperatures, α,β-unsaturated 1,4-diketones can also be prepared.The reduction of the intermediate α,β-unsaturated 1,4-diketones probably proceeds by insertion of a palladium hydride, formed in situ by reaction of a Pd(II) complex with Bu3SnCl, followed by hydrolysis of the intermediate palladium enolate.
- Echavarren, Antonio M.,Perez, Marta,Castano, Ana M.,Cuerva, Juan M.
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p. 4179 - 4185
(2007/10/02)
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