- Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands
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The asymmetric hydrogenation of 2,2,2-trifluoroacetophenones and aryl perfluoroalkyl ketones was developed using a unique, well-defined chloride-bridged dinuclear rhodium(III) complex bearing Josiphos-type diphosphine ligands. These complexes were prepared from [RhCl(cod)]2, Josiphos ligands, and hydrochloric acid. As catalyst precursors, they allow for the efficient and enantioselective synthesis (up to 99 % ee) of chiral secondary alcohols with perfluoroalkyl groups. This system does not require an activating base for the hydrogenation of 2,2,2-trifluoroacetophenones. Additionally, the enantioselective C=O hydrogenations of 2-phenyl-3-(haloacetyl)-indoles, a class of privileged structures in medicinal chemistry, is reported for the first time.
- Brüning, Fabian,Nagae, Haruki,K?ch, Daniel,Mashima, Kazushi,Togni, Antonio
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supporting information
p. 10818 - 10822
(2019/07/31)
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- METHOD FOR PRODUCING TRIFLUOROMETHYL GROUP-CONTAINING ALCOHOLS
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PROBLEM TO BE SOLVED: To provide a method for producing trifluoromethyl group-containing alcohols useful as synthetic intermediates for medicines and agrochemicals. SOLUTION: This invention relates to a method for producing trifluoromethyl group-containing alcohols expressed by a formula (2), comprising: making carbonyl compounds expressed by a formula (1) react with trifluoromethane in an organic solvent in the presence of polyvalent ethers and potassium tert-butoxide, or kalium hexamethyldisilazide. (R1 and R2 are each independently a phenyl group etc.; R2 may combine with R1, to form a ring, and both R1 and R2 are not hydrogen atoms). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0081; 0082; 0092
(2018/04/10)
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- Amidinate salt of hexafluoroacetone hydrate for the preparation of fluorinated compounds by the release of trifluoroacetate
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A powerful, new reagent, an amidinate salt of hexafluoroacetone hydrate, is an air-stable salt that can be used for the preparation of fluorinated organic molecules. Nucleophilic trifluoromethylation reactions are demonstrated following the base-promoted release of trifluoroacetate. This reagent is soluble in many polar organic solvents and produces fluoroform, following the release of trifluoroacetate. Reactions with this reagent and common electrophiles provide excellent yields of trifluoromethylated products.
- Riofski, Mark V.,Hart, Allison D.,Colby, David A.
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supporting information
p. 208 - 211
(2013/04/10)
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- Trifluoromethylation of ketones and aldehydes with Bu3SnCF 3
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The (trifluoromethyl)stannane reagent, Bu3SnCF3, was found to react under CsF activation with ketones and aldehydes to the corresponding trifluoromethylated stannane ether intermediates at room temperature in high yield. Only a mildly acidic extraction (aqueous NH 4Cl) is required to release the corresponding trifluoromethyl alcohol products. The protocol is compatible with acid-sensitive functional groups.
- Sanhueza, Italo A.,Bonney, Karl J.,Nielsen, Mads C.,Schoenebeck, Franziska
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p. 7749 - 7753
(2013/09/02)
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- Nucleophilic trifluoromethylation of carbonyl compounds: Trifluoroacetaldehyde hydrate as a trifluoromethyl source
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A feasible nucleophilic trifluoromethylating protocol has been developed using trifluoroacetaldehyde hydrate as an atom-economical trifluoromethyl source. The reaction was found to be applicable to the nucleophilic trifluoromethylation of a broad spectrum of carbonyl compounds with satisfactory yields in general. DFT calculations have been performed to provide mechanistic insight into the present and related reactions employing 2,2,2-trifluoro-1- methoxyethanol and hexafluoroacetone hydrate.
- Surya Prakash,Zhang, Zhe,Wang, Fang,Munoz, Socrates,Olah, George A.
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p. 3300 - 3305
(2013/06/27)
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- COMPOSITIONS AND PROCESSES OF PREPARING AND USING THE SAME
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The present invention relates to compositions, for example, the DBU/Hexafluoroacetone hydrate salt, and processes of preparing and using the same for the modification of chemical compounds via the release of trifluoroacetate. The DBU/Hexafluoroacetone hydrate salt can perform trifluoromethylation reactions on chemical compounds, such as carbonyl group-containing compounds.
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Page/Page column 36
(2012/10/08)
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- Regioselective substitution of phenols with trifluoroacetaldehyde ethyl hemiacetal
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2,2,2-Trifluoroethanols are of great interest because of their unique physical, chemical, and biological properties. Trifluoroacetaldehyde is a very efficient reagent for obtaining 2,2,2-trifluoroethanols. Because it is unavailable commercially, its hemia
- Gong,Kato,Kimoto
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p. 377 - 383
(2007/10/03)
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- Nucleophilic trifluoromethylation and difluorination of substituted aromatic aldehydes with Ruppert's and Deoxofluor? reagents
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Efficient, high yield syntheses of 2,2,2-trifluoro-1-(N,N-dialkylaminophenyl)-ethanols (3a, b) and 2,2,2-trifluoro-1-(hydroxyaryl)ethanols (6c-g) by reacting Ruppert's reagent, (trifluoromethyl)trimethylsilane (TMSCF3), with appropriate substra
- Singh, Rajendra P.,Chakraborty, Debashis,Shreeve, Jean'Ne M.
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p. 153 - 160
(2007/10/03)
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- Fluoroform: An efficient precursor for the trifluoromethylation of aldehydes
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Fluoroform is shown to be an efficient trifluoromethylating agent when deprotonated using standard reagents in DMF. The important role of DMF as a solvent but also as a reactant was demonstrated.
- Folléas, Beno?t,Marek, Ilan,Normant, Jean-F.,Saint-Jalmes, Laurent
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p. 275 - 283
(2007/10/03)
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- Facile substitution of N,N-dimethylanilines and phenols with trifluoroacetaldehyde ethyl hemiacetal
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2,2,2-Trifluoro-1-(N,N-dimethylaminophenyl)ethanols were easily formed in excellent yields by electrophilic substitution between N,N- dimethylanilines 1a, b and trifluoroacetaldehyde ethyl hemiacetal (TFAE). The corresponding substitution of phenols 2a-e
- Gong, Yuefa,Kato, Katsuya,Kimoto, Hiroshi
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p. 1403 - 1404
(2007/10/03)
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- Aromatic Substitution Reactions of Amines with Ring-Substituted 1-Phenyl-2,2,2-trifluoroethyl Carbocations
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4-MeOArCH(CF3)Br in 20percent acetonitrile in water reacts with Me2NH to form 4-MeOArCH(CF3)NMe2 and 4-Me2NArCH(CF3)NMe2, with MeO(CH2)2NH2 to form 4-MeOArCH(CF3)NH(CH2)2OMe and 4-MeO(CH2)2NHArCH(CF3)NH(CH2)2OMe, and with a mixture of MeO(CH2)2NH2 and Me2
- Richard, John P.
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p. 6735 - 6744
(2007/10/02)
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- PALLADIUM AND NICKEL-CATALYZED PERFLUOROALKYLATION OF ALDEHYDES USING ZINC AND PERFLUOROALKYL HALIDES
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A room temperature method for the conversion of perfluoroalkyl iodides to α-perfluoroalkyl carbinols under Pd or Ni catalysis is reported.The use of trifluoromethyl bromide provides an economical procedure for trifluoromethyl substituted carbinols.
- O'Reilly, Neil J.,Maruta, Masamichi,Ishikawa, Nobuo
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p. 517 - 520
(2007/10/02)
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- The reduction of aryl trifluoromethyl ketones by sodium borohydride. The hydride transfer process
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The rates of reduction of 17 aryl trifluoromethyl ketones by sodium borohydride in 2-propanol have been measured.The rho (ρ) value is 3.12, excluding the 4-amino and 4-dimethylamino groups, which both lower the rate to a greater extent than their ? values predict.The close correspondence between substituent effects for hydride addition in the methyl and trifluoromethyl series (excluding the amino groups) suggests that normal substituent effects are to be expected for oxidation processes involving hydride removal in trifluoromethyl compounds.The present results are consistent with the oxidation of aryl trifluoromethyl carbi ols by permanganate taking place by hydrogen atom abstraction.The effect of substituents on the rate of reduction of the trifluoromethyl ketones is almost identical to that on the equilibrium constant for formation of the ketone hydrates.The application of the reactivity-selectivity principle to the reduction reaction is also considered.Reduction of the 4-ethyl compound has ΔH = 2.7 kcal mol-1 and ΔS = -38 cal deg-1 mol-1.
- Stewart, Ross,Teo, K. C.
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p. 2491 - 2496
(2007/10/02)
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- The reduction of aryl trifluoromethyl ketones by N-carbamoylmethyl-1,4-dihydronicotinamide
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The reaction of 15 aryl trifluoromethyl ketones with N-carbamoylmethyl-1,4-dihydronicotinamide has been studied in aqueous sulfolane buffer.The unsubstituted ketone and those containing electron-withdrawing groups in the ring have the following reaction characteristics: (a) a high yield of alcohol is obtained, (b) the observed reaction rate is independent of ring substituent; however, when corrections are made for degree of hydration of the ketones the rate is correlated with Hammett ? values with a rho of 1.98, (c) a secondary isotope effect of approximately 1.08 and primary isotope effects of 1.45-1.62 are observed at 43.4 deg C for the reaction of the dihydronicotinamide containing one or two atoms of deuterium at C-4, (d) ΔH = 15.2 kcal mol-1, and ΔS = -27.0 cal deg-1 mol-1 for the unsubstituted compound, uncorrected for ketone hydration; ΔS for reaction of the unhydrated ketone and dihydronicotinamide is estimated to be -45 to -50 cal deg-1 mol-1.The mechanism for the reduction is consistent with hydride transfer from reductant to oxidant, very possibly accompanied by blind-alley formation of an adduct between ketone hydrate and dihydronicotinamide.Ketones containing electron-donating groups in the ring react with the dihydronicotinamide in some undetermined way, giving little or no alcohol as product.
- Stewart, Ross,Teo, K. C.,Ng, L. K.
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p. 2497 - 2503
(2007/10/02)
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