- Csp3-H Trifluoromethylation of Unactivated Aliphatic Systems
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A straightforward method for the undirected trifluoromethylation of unactivated methylene units was developed. The reaction proceeds in aqueous acetonitrile with Grushin's reagent, bpyCu(CF3)3, under broad-spectrum white-light irradiation. The trifluoromethylation tolerates a wide range of functional groups including ketones, esters, nitriles, amides, alcohols, and carboxylic acids. The C-H cleavage step is performed via intermolecular H atom abstraction, and the selectivities across a range of methylene units are reported. Mechanistic studies offer a general reaction coordinate for the overall transformation.
- He, Jiachen,Nguyen, Truong N.,Guo, Shuo,Cook, Silas P.
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supporting information
p. 702 - 705
(2021/02/01)
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- Direct C(sp3)?H Trifluoromethylation of Unactivated Alkanes Enabled by Multifunctional Trifluoromethyl Copper Complexes
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A mild and operationally simple C(sp3)?H trifluoromethylation method was developed for unactivated alkanes by utilizing a bench-stable CuIII complex, bpyCu(CF3)3, as the initiator of the visible-light photoinduced reaction, the source of a trifluoromethyl radical as a hydrogen atom transfer reagent, and the source of a trifluoromethyl anion for functionalization. The reaction was initiated by the generation of reactive electrophilic carbon-centered CF3 radical through photoinduced homolytic cleavage of bpyCu(CF3)3, followed by hydrogen abstraction from an unactivated C(sp3)?H bond. Comprehensive mechanistic investigations based on a combination of experimental and computational methods suggested that C?CF3 bond formation was enabled by radical–polar crossover and ionic coupling between the resulting carbocation intermediate and the anionic CF3 source. The methylene-selective reaction can be applied to the direct, late-stage trifluoromethylation of natural products and bioactive molecules.
- Choi, Geunho,Lee, Geun Seok,Park, Beomsoon,Kim, Dongwook,Hong, Soon Hyeok
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supporting information
p. 5467 - 5474
(2021/01/20)
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- Synthesis method of 4-substituent cyclohexanone liquid crystal intermediate
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The invention discloses a synthesis method of a 4-substituent cyclohexanone liquid crystal intermediate, which comprises the following step: carrying out oxidation catalytic reaction on 4-substituent cyclohexanol under the action of trichloroisocyanide urea to obtain the 4-substituent cyclohexanone liquid crystal intermediate. The method is high in reaction selectivity, high in yield, environment-friendly, simple in post-treatment and suitable for industrial production.
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Paragraph 0056-0058
(2021/05/19)
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- Aliphatic C-H Bond Oxidation with Hydrogen Peroxide Catalyzed by Manganese Complexes: Directing Selectivity through Torsional Effects
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Substituted N-cyclohexyl amides undergo aliphatic C-H bond oxidation with H2O2 catalyzed by manganese complexes. The reactions are directed by torsional effects leading to site-selective oxidation of cis-1,4-, trans-1,3-, and cis-1,2-cyclohexanediamides. The corresponding diastereoisomers are unreactive under the same conditions. Competitive oxidation of cis-trans mixtures of 4-substituted N-cyclohexylamides leads to quantitative conversion of the cis-isomers, allowing isolation and successive conversion of the trans-isomers into densely functionalized oxidation products with excellent site selectivity and good enantioselectivity.
- Milan, Michela,Bietti, Massimo,Costas, Miquel
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supporting information
p. 2720 - 2723
(2018/05/22)
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- Spectroscopic and X-ray crystallographic evidence for electrostatic effects in 4-substituted cyclohexanone-derived hydrazones, imines, and corresponding salts
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The axial conformer of several 4-substituted cyclo-hexanone hydrazone salts was found to predominate in solution. Changes in the charge of the molecule and the polarity of the solvent led to changes in the conformational preference of each molecule that were consistent with electrostatic stabilization of the axial conformer. H NMR spectroscopic analysis was utilized to determine the structure of cyclohexanone-derived substrates by comparison to conformationally restricted trans-decalone derivatives and computational models. X-ray crystallography demonstrated that the axial configuration of a pendant benzyloxy group is the preferred conformation of an iminium ion in the solid state. The structure of a neutral hydrazone was also determined to favor the axial configuration for a pendant benzyloxy group in the solid state.
- Dibble, David J.,Ziller, Joseph W.,Woerpef
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experimental part
p. 7706 - 7719
(2011/12/02)
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- MELANOCORTIN RECEPTOR AGONISTS
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The present invention relates to a compound of the following formula 1, pharmaceutically acceptable salt and isomer thereof effective as agonist of melanocortin receptor, and an agonistic composition of melanocortin receptor comprising the same as active ingredient.
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Page/Page column 27-28
(2008/06/13)
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- Oxidation of alcohols to carbonyl compounds with CrO3· SiO2 in supercritical carbon dioxide
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Supercritical carbon dioxide (scCO2) is an effective reaction medium to perform the oxidation of primary and secondary aliphatic alcohols to the corresponding carbonyl compounds with chromium trioxide supported on silica. These reactions were performed by flowing a solution of the alcohol in scCO2 through a column containing the supported reagent and recovering the product by depressurization. This method avoids the use of organic solvents and the contamination of the products with chromium species.
- Gonzalez-Nunez, Maria Elena,Mello, Rossella,Olmos, Andrea,Accrete, Rafael,Asensio, Gregorio
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p. 1039 - 1042
(2007/10/03)
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- Trifluoromethylcyclohexane as a new solvent? Limits of use
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Reactivity and stability of trifluoromethylcyclohexane (TFMC) has been investigated towards various reagents, in order to evaluate its possible use as solvent. TFMC is stable in most oxidizing conditions, indicating the protective effect of a fluoroalkyl substituent towards oxidation, and surprisingly, it is also very stable towards strong bases. TFMC has also been assessed as a chlorinated solvent substitute in some reactions. It is clearly adapted as a CCl4 substitute in allylic bromination reaction.
- Legros, Julien,Crousse, Benoit,Bonnet-Delpon, Danièle,Bégué, Jean-Pierre,Maruta, Masamichi
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p. 4067 - 4070
(2007/10/03)
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- Diels-Alder Reactions of (Trifluoromethyl)ethene and (Trifluoromethyl)styrenes with Functionalized Butadiens
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The-Alder reactions of (trifluoromethyl)ethene (1) with 2-(trimethylsiloxy)buta-1,3-diene (2), 2--1,3-butadiene (4), and 1-methoxy-3-(trimethylsiloxy)buta-1,3-diene (6) were carried out to give the corresponding cycloadducts in 17-38percent yields.It was found that the former two cycloadducts were a mixture of para (major) and meta (minor) isomers, while the latter was the para isomer exlusively.Similary, β-(trifluoromethyl)-4-(methoxycarbonyl)styrene (9) and β-(trifluoromethyl)-4-nitrostyrene (10) were allowed to react with 4 and 6, giving the corresponding cycloadducts in 56-90percent yields.The regioselectivity of the reaction on using 6 as the diene turned out to be extremely high, leading to the formation of only one regioisomer.The substituent effect of the trifluoromethyl group in the Diels-Alder reaction in terms of regioselectivity is discussed.
- Ojima, Iwao,Yatabe, Momoko,Fuchikami, Takamasa
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p. 2051 - 2055
(2007/10/02)
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- Trifluoromethyl derivatives of cyclohexanol and cyclohexanone and their reactions
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The catalytic hydrogenation of mono- and bistrifluoromethylphenols was investigated, and the structure of the obtained trifluoromethylcyclohexanols was established.Methods were developed for the production of trifluoromethyl derivatives of caprolactam and adipic acid.
- Zalesskaya, I. M.,Blakitnyi, A. N.,Saenko, E. P.,Fialkov, Yu. A.,Yagupol'skii, L. M.
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p. 1031 - 1038
(2007/10/02)
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