- Silver-catalyzed decarboxylative C–H functionalization of cyclic aldimines with aliphatic carboxylic acids
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Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields (32%–91%). In addition, a gram-scale reaction, late-stage modification of drug, synthetic transformation of the product, and further application of the catalytic strategy were also performed. Preliminary studies indicate that the reaction undergoes a radical process.
- Wang, Jingjing,Liu, Xue,Wu, Ziyan,Li, Feng,Qin, Tingting,Zhang, Siyuan,Kong, Weiguang,Liu, Lantao
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- Distal-Bond-Selective C?C Activation of Ring-Fused Cyclopentanones: An Efficient Access to Spiroindanones
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A site-selective rhodium-catalyzed C?C activation of ring-fused cyclopentanones was achieved to afford efficient access to a range of spiroindanones. The use of bulky 2-amino-6-picoline as a cocatalyst is key to the excellent selectivity of this C?C bond cleavage in cyclopentanones.
- Xia, Ying,Wang, Jianbo,Dong, Guangbin
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- Silver-Catalyzed Decarboxylative Trifluoromethylation of Aliphatic Carboxylic Acids
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The silver-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids is described. With AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of aliphatic carboxylic acids with (bpy)C
- Tan, Xinqiang,Liu, Zhonglin,Shen, Haigen,Zhang, Pei,Zhang, Zhenzhen,Li, Chaozhong
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supporting information
p. 12430 - 12433
(2017/09/25)
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- Catalytic activation of carbon-carbon bonds in cyclopentanones
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In the chemical industry, molecules of interest are based primarily on carbon skeletons. When synthesizing such molecules, the activation of carbon-carbon single bonds (C-C bonds) in simple substrates is strategically important: it offers a way of disconnecting such inert bonds, forming more active linkages (for example, between carbon and a transition metal) and eventually producing more versatile scaffolds. The challenge in achieving such activation is the kinetic inertness of C-C bonds and the relative weakness of newly formed carbon-metal bonds. The most common tactic starts with a three- or four-membered carbon-ring system, in which strain release provides a crucial thermodynamic driving force. However, broadly useful methods that are based on catalytic activation of unstrained C-C bonds have proven elusive, because the cleavage process is much less energetically favourable. Here we report a general approach to the catalytic activation of C-C bonds in simple cyclopentanones and some cyclohexanones. The key to our success is the combination of a rhodium pre-catalyst, an N-heterocyclic carbene ligand and an amino-pyridine co-catalyst. When an aryl group is present in the C3 position of cyclopentanone, the less strained C-C bond can be activated; this is followed by activation of a carbon-hydrogen bond in the aryl group, leading to efficient synthesis of functionalized α-tetralones - a common structural motif and versatile building block in organic synthesis. Furthermore, this method can substantially enhance the efficiency of the enantioselective synthesis of some natural products of terpenoids. Density functional theory calculations reveal a mechanism involving an intriguing rhodium-bridged bicyclic intermediate.
- Xia, Ying,Lu, Gang,Liu, Peng,Dong, Guangbin
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p. 546 - 550
(2017/04/01)
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- Silver-Catalyzed Radical Transformation of Aliphatic Carboxylic Acids to Oxime Ethers
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Oximes and oxime ethers are privileged building blocks and can be conveniently converted to ketones, amines, hydroxylamines, and nitriles. We describe the catalytic decarboxylation of aliphatic carboxylic acids to oxime ethers. With AgNO3 as the catalyst, valuable oxime ethers bearing various substituents could be easily obtained. The broad substrate scope, easy accessibility of aliphatic carboxylic acids, and mild reaction conditions make this strategy immediately applicable to the synthesis, late-stage functionalization, and modification of biologically active compounds. Experimental studies show the reaction undergoes a radical process.
- Zhu, Yuchao,Wen, Xiaojin,Song, Song,Jiao, Ning
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p. 6465 - 6472
(2016/10/14)
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- Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution
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We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH3CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation.
- Liu, Chao,Wang, Xiaoqing,Li, Zhaodong,Cui, Lei,Li, Chaozhong
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supporting information
p. 9820 - 9823
(2015/08/24)
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- Silver-Catalyzed Decarboxylative Azidation of Aliphatic Carboxylic Acids
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The catalytic decarboxylative nitrogenation of aliphatic carboxylic acids for the synthesis of alkyl azides is reported. A series of tertiary, secondary, and primary organoazides were prepared from easily available aliphatic carboxylic acids by using K2S2O8 as the oxidant and PhSO2N3 as the nitrogen source. The EPR experiment sufficiently proved that an alkyl radical process was generated in the process, and DFT calculations further supported the SET process followed by a stepwise SH2 reaction to afford azide product.
- Zhu, Yuchao,Li, Xinyao,Wang, Xiaoyang,Huang, Xiaoqiang,Shen, Tao,Zhang, Yiqun,Sun, Xiang,Zou, Miancheng,Song, Song,Jiao, Ning
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supporting information
p. 4702 - 4705
(2015/10/12)
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- Silver-catalyzed decarboxylative alkynylation of aliphatic carboxylic acids in aqueous solution
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C(sp3)-C(sp) bond formations are of immense interest in chemistry and material sciences. We report herein a convenient, radical-mediated and catalytic method for C(sp3)-C(sp) cross-coupling. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, various aliphatic carboxylic acids underwent decarboxylative alkynylation with commercially available ethynylbenziodoxolones in aqueous solution under mild conditions. This site-specific alkynylation is not only general and efficient but also functional group compatible. In addition, it exhibits remarkable chemo- and stereoselectivity.
- Liu, Xuesong,Wang, Zhentao,Cheng, Xiaomin,Li, Chaozhong
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supporting information
p. 14330 - 14333
(2012/10/30)
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- Design, synthesis, structure, and dehydrogenation reactivity of a water soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group
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5-Trimethylammonio-1, 3-dioxo-1, 3-dihydro-1λ5-benzo[d][1, 2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various β-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility.2011 American Chemical Society.
- Cui, Li-Qian,Dong, Zhi-Lei,Liu, Kai,Zhang, Chi
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supporting information; experimental part
p. 6488 - 6491
(2012/02/02)
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- Activation of 1,1-difluoro-1-alkenes with a transition-metal complex: Palladium(II)-catalyzed friedel - crafts-type cyclization of 4,4-(difluorohomoallyl)arenes
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(Chemical Equation Presented) Cationic palladium(II) ([Pd(MeCN) 4](BF4)2) provides the first transition-metal-catalyzed method for electrophilic activation of electron-deficient 1,1-difluoro-1-alkenes, which allows their Friedel-Crafts-type cyclization with an intramolecular aryl group via a Wacker-type process. By using BF3·OEt2, the cyclization was effected by a catalytic amount of the palladium without its reoxidation.
- Yokota, Misaki,Fujita, Daishi,Ichikawa, Junji
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p. 4639 - 4642
(2008/03/15)
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- Friedel-crafts cyclization of 1,1-difluoroalk-1-enes: Synthesis of benzene-fused cyclic ketones via α-fluorocarbocations
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1,1-Difluoroalk-1-enes bearing a phenyl group at the C-3, -4, or -5 position, readily obtained from 2,2,2-trifluoroethyl p-toluenesulfonate, are treated with FSO3H·SbF5 to undergo Friedel-Crafts cyclization in (CF3)2CHOH. The cyclization takes place via α-fluorocarbocations, followed by spontaneous hydrolysis of the C-F bond to afford bicyclic ketones including a five, six, or seven-membered ring in good yield.
- Ichikawa, Junji,Jyono, Hideharu,Kudo, Takao,Fujiwara, Masaki,Yokota, Misaki
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- Ionic Hydrogenation of 1-Naphthol Derivatives with Alkanes in the Presence of Aluminum Halides
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Reactions of 1-naphthol, 4-methyl-1-naphthol, 3-phenyl-1-naphthol, and 4-chloro-1-naphthol with cyclohexane, as well as of 1-naphthol with methylcyclopentane, pentane, isobutane, and propane, in the presence of excess aluminum chloride or bromide yield α-tetralone derivatives as a result of regioselective ionic hydrogenation. Abstraction of the hydride ion from alkane is effected by the protonated complex of the keto form of the naphthol with aluminum halide.
- Koltunov,Subbotina,Repinskaya
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p. 689 - 693
(2007/10/03)
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- Synthese de methoxycarbonylindenes, dihydro-1,2 naphtalenes et benzocycloheptene. Obtention des indanones-1, des tetralones-1 et de la benzosuberone correspondantes
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The synthesis of methoxycarbonylindenes, 1,2-dihydro-naphtalenes, and benzocycloheptene starting from the corresponding 1-indanones, 1-tetralones, and benzosuberone is reported.The starting ketones were synthesized by methods described in the literature which were optimized; in some cases new processes are described.
- Verbel, Joel,Carrie, Robert
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p. 116 - 124
(2007/10/02)
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