- 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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- Niacin receptor agonists, compositions containing such compounds and methods of treatment
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The present invention encompasses compounds of Formula I: as well as pharmaceutically acceptable salts and hydrates thereof, that are useful for treating atherosclerosis, dyslipidemias and the like. Pharmaceutical compositions and methods of use are also included.
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Page/Page column 31; 51
(2010/11/25)
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- Regioselective 1,4-trifluoromethylation of α,β-enones using 'protect-in-situ' methodology
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In a convenient and efficient procedure, the nucleophilic 1,4-trifluoromethylation of several α,β-enones using (trifluoromethyl)trimethylsilane was achieved. The high regioselectivity of the reaction has been reached by blocking the carbonyl moiety of the electrophile with a bulky aluminum-centered Lewis acid.
- Sevenard, Dmitri V.,Sosnovskikh, Vyacheslav Ya.,Kolomeitsev, Alexander A.,K?nigsmann, Martin H.,R?schenthaler, Gerd-Volker
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p. 7623 - 7627
(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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- Preparation of Trifluoromethyl and Other Perfluoroalkyl Compounds with (Perfluoroalkyl)trimethylsilanes
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The preparation of a variety of novel perfluoroalkyl-substituted compounds in high yields using easily prepared (perfluoroalkyl)trimethylsilanes (1a - c) is described. (Trifluoromethyl)-, (pentafluoroethyl)-, and (heptafluoropropyl)trimethylsilane, 1a - c, respectively, react readily with carbonyl compounds, such as aldehydes and ketones, by a fluoride-initiated catalytic process.Fluoride-initiated addition of 1 to a carbonyl group generates an oxyanionic species which then further catalyzes the reaction.Even enolizable carbonyl compounds react cleanly under the reaction conditions.A study of the scope of the reactivity of 1a toward other carbonyl groups in esters, lactones and an acid chloride was also carried out.Thus 1a reacts cleanly with five- and six-membered ring lactones.However, unactivated esters do not react under the reaction conditions.The acid chloride reacts with 1a to give a mixture of products.
- Krishnamurti, Ramesh,Bellew, Donald R.,Prakash, G. K. Surya
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p. 984 - 989
(2007/10/02)
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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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