- Highly enantioselective construction of CF3-bearing all-carbon quaternary stereocenters: Hiral spiro-fused bisoxazoline ligands with 1,1′-binaphthyl sidearm for asymmetric Michael-type Friedel-Crafts reaction
-
A novel class of chiral spiro-fused bisoxazoline ligands possessing a deep chiral pocket was prepared. The developed ligands have been employed in the nickel-catalyzed highly enantioselective Michael-type Friedel-Crafts reaction, affording the products bearing a trifluoromethylated all-carbon quaternary stereocenter with moderate to excellent yields (up to 99%) and good to excellent enantioselectivies (up to > 99.9% ee). Moreover, a proposed model of chiral pocket revealed that the attack of indole from the Re-face of β-CF3-β-disubstituted nitroalkene was favorable.
- Bao, Robert Li-Yuan,Fu, Kang,Shi, Lei
-
-
- Synthesis of Unsymmetric Triarylmethanes Bearing CF 3-Substituted All-Carbon Quaternary Stereocenters: 1,6-Arylation of δ-Trifluo romethyl Substituted para -Quinone Methides
-
Pre-synthesized δ-CF 3-δ-aryl-disubstituted para -quinone methides bearing δ-substituents were identified as isolable and storable substrates for 1,6-arylation reactions. A broad range of electron-rich arenes and heteroarenes participated in the arylation process, furnishing a wide array of unsymmetrical CF 3-substituted triarylmethanes in high efficiency. The mild and expeditious protocol exhibited broad scopes of both arene and para -quinone methide components.
- Ma, Yingang,Pang, Jingxiang,Pan, Xiaoguang,Ma, Shutao,Liu, Xigong,Liu, Lei
-
supporting information
p. 1619 - 1622
(2020/09/15)
-
- One-Pot Successive Turbo Grignard Reactions for the Facile Synthesis of α-Aryl-α-Trifluoromethyl Alcohols
-
A novel straightforward one-pot methodology for two successive turbo Grignard reagent (iPrMgCl·LiCl) reactions, was developed for a facile synthesis of α-aryl-α-trifluoromethyl alcohols, motifs of value in pharmaceutical chemistry. The method displayed broad functional group tolerance, including reducible groups. Dual roles of iPrMgCl·LiCl were exploited in the tandem reaction with commercially available iodoarenes or iodoheteroarenes and 2,2,2-trifluoroethyl trifluoroacetate. The process encompasses three successive reactions in a one-pot process: the iPrMgCl·LiCl-mediated iodine/magnesium-exchange reaction of iodoarenes or iodoheteroarenes; nucleophilic addition of various generated aryl or heteroarylmagnesium reagents to 2,2,2-trifluoroethyl trifluoroacetate; and the reduction of in-situ generated aryl trifluoromethyl ketones with iPrMgCl·LiCl, to produce the corresponding α-aryl or α-heteroaryl-α-trifluoromethyl alcohols bearing various substituents, including reducible functional groups in good to excellent yields.
- Kani, Ryunosuke,Inuzuka, Toshiyasu,Kubota, Yasuhiro,Funabiki, Kazumasa
-
supporting information
p. 4487 - 4493
(2020/06/01)
-
- A Hammett Study of Clostridium acetobutylicum Alcohol Dehydrogenase (CaADH): An Enzyme with Remarkable Substrate Promiscuity and Utility for Organic Synthesis
-
Described is a physical organic study of the reduction of three sets of carbonyl compounds by the NADPH-dependent enzyme Clostridium acetobutylicum alcohol dehydrogenase (CaADH). Previous studies in our group have shown this enzyme to display broad substrate promiscuity, yet remarkable stereochemical fidelity, in the reduction of carbonyl compounds, including α-, β- and γ-keto esters (d -stereochemistry), as well as α,α-difluorinated-β-keto phosphonate esters (l -stereochemistry). To better mechanistically characterize this promising dehydrogenase enzyme, we report here the results of a Hammett linear free-energy relationship (LFER) study across three distinct classes of carbonyl substrates; namely aryl aldehydes, aryl β-keto esters and aryl trifluoromethyl ketones. Rates are measured by monitoring the decrease in NADPH fluorescence at 460 nm with time across a range of substrate concentrations for each member of each carbonyl compound class. The resulting v 0 versus [S] data are subjected to least-squares hyperbolic fitting to the Michaelis-Menton equation. Hammett plots of log(V max) versus σ X yield the following Hammett parameters: (i) for p -substituted aldehydes, ρ = 0.99 ± 0.10, ρ = 0.40 ± 0.09; two domains observed, (ii) for p -substituted β-keto esters ρ = 1.02 ± 0.31, and (iii) for p -substituted aryl trifluoromethyl ketones ρ = -0.97 ± 0.12. The positive sign of ρ indicated for the first two compound classes suggests that the hydride transfer from the nicotinamide cofactor is at least partially rate-limiting, whereas the negative sign of ρ for the aryl trifluoromethyl ketone class suggests that dehydration of the ketone hydrate may be rate-limiting for this compound class. Consistent with this notion, examination of the 13 C NMR spectra for the set of p -substituted aryl trifluo romethyl ketones in 2percent aqueous DMSO reveals significant formation of the hydrate (gem -diol) for this compound family, with compounds bearing the more electron-withdrawing groups showing greater degrees of hydration. This work also presents the first examples of the CaADH-mediated reduction of aryl trifluoromethyl ketones, and chiral HPLC analysis indicates that the parent compound α,α,α-trifluoroacetophenone is enzymatically reduced in 99percent ee and 95percent yield, providing the (S)-stereoisomer, suggesting yet another compound class for which this enzyme displays high enantioselectivity.
- Berkowitz, David B.,Kudalkar, Gaurav P.,Lee, Joshua D.,Tiwari, Virendra K.
-
p. 237 - 247
(2020/02/18)
-
- Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands
-
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
-
supporting information
p. 10818 - 10822
(2019/07/31)
-
- Visible light-promoted umpolung coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines
-
Tertiary alcohols bearing a trifluoromethyl group are of considerable medicinal interest. Using an umpolung strategy, we herein report the first intermolecular reductive cross-coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines with the aid of a Br?nsted acid catalyst upon visible-light irradiation. This metal-free reaction is operationally simple and performed at ambient temperature, allowing access to desired tertiary alcohols with tri-/difluoromethyl groups in moderate to excellent yields. The commercially available and easily handled Hantzsch ester effectively serves as an electron donor, as well as a hydrogen atom source.
- Xu, Xiao,Min, Qing-Qiang,Li, Na,Liu, Feng
-
supporting information
p. 11017 - 11020
(2018/10/08)
-
- Oxidation of α-trifluoromethyl and non-fluorinated alcohols: Via the merger of oxoammonium cations and photoredox catalysis
-
We present an alcohol oxidation strategy to access α-trifluoromethyl ketones (TFMKs) merging catalytic oxoammonium cation oxidation with visible-light photoredox catalysis. This work uses 4-acetamido-(2,2,6,6-tetramethyl-piperidin-1-yl)oxyl as an organic oxidant capable of generating TFMKs in good yields. The methodology serves as an improvement over previous reports of an analogous oxidation strategy requiring superstoichiometric quantities of oxidant. Both primary and secondary non-fluorinated alcohols can also be oxidised in good yields.
- Pistritto, Vincent A.,Paolillo, Joshua M.,Bisset, Kathryn A.,Leadbeater, Nicholas E.
-
p. 4715 - 4719
(2018/07/06)
-
- HORMONE RECEPTOR MODULATORS FOR TREATING METABOLIC CONDITIONS AND DISORDERS
-
The invention relates to activators of FXR useful in the treatment of autoimmune disorders, liver disease, intestinal disease, kidney disease, cancer, and other diseases in which FXR plays a role, having the Formula (I): (I), wherein L1, A, X1, X2, R1, R2, and R3 are described herein.
- -
-
Page/Page column 288
(2018/03/25)
-
- FLUOROALKYLATING AGENT
-
Problem to be Solved It is intended to provide an industrially preferable fluoroalkylating agent and use thereof. Solution The present invention provides a fluoroalkylating agent represented by the general formula (1) wherein R1 is a C1 to C8 fluoroalkyl group; R2 and R3 are each independently a C1 to C12 alkyl group or the like; Y1 to Y4 are each independently a hydrogen atom, a halogen atom, or the like; and X? is a monovalent anion. A compound of the general formula (3): R4—S—R1 having an introduced C1 to C8 fluoroalkyl group is easily obtained by reacting a compound of the general formula (2): R4—S—Z wherein R4 is a hydrocarbon group or the like; and Z is a leaving group, with the compound of the general formula (1).
- -
-
Paragraph 1333-1334
(2018/01/11)
-
- Is Magnetic Bistability of Carbenes a General Phenomenon? Isolation of Simple Aryl(trifluoromethyl)carbenes in Both Their Singlet and Triplet States
-
p-Tolyl(trifluoromethyl)carbene and the related fluorenyl(trifluoromethyl)carbene were synthesized in solid argon and characterized by IR, UV-vis, and electron paramagnetic resonance spectroscopy as well as by quantum mechanical calculations. The carbenes
- Tsegaw, Yetsedaw A.,Kadam, Pritam E.,T?tsch, Niklas,Sanchez-Garcia, Elsa,Sander, Wolfram
-
p. 12310 - 12316
(2017/09/12)
-
- Flow trifluoromethylation of carbonyl compounds by Ruppert-Prakash reagent and its application for pharmaceuticals, efavirenz and HSD-016
-
The Ruppert-Prakash reagent is the most powerful and well-documented reagent for trifluoromethylation. Despite its versatility, no general method exists for its use in a flow system. Here we report the first flow trifluoromethylation of carbonyl compounds
- Okusu, Satoshi,Hirano, Kazuki,Yasuda, Yoshimasa,Tokunaga, Etsuko,Shibata, Norio
-
p. 82716 - 82720
(2016/11/11)
-
- A method of manufacturing a trifluoromethyl group-containing compound
-
PROBLEM TO BE SOLVED: To provide a method for producing a trifluoromethyl group-containing compound useful as a synthetic intermediate for a pharmaceutical or an agricultural chemical product.SOLUTION: There is provided a method for producing a trifluoromethyl group-containing compound represented by the following general formula (2) which is obtained by reacting a carbonyl compound having a specific structure with trifluoromethane and an organic base in an organic solvent (wherein, Rrepresents a methyl group, an ethyl group, a linear, branched or cyclic alkyl group having 3 to 10 carbon atoms, a phenyl group, a substituted phenyl group, a naphthyl group, a substituted naphthyl group, an ethenyl group, a 2-phenylethenyl group, a 9-anthryl group or a hetero ring; Rrepresents a hydrogen atom, a methyl group or a phenyl group.)
- -
-
Paragraph 0046; 0050; 0051
(2018/02/10)
-
- Catalytic highly enantioselective transfer hydrogenation of β-trifluoromethyl nitroalkenes. An easy and general entry to optically active β-trifluoromethyl amines
-
In the presence of a thiourea catalyst, β-CF3 nitroalkenes react with Hantzsch esters in a highly enantioselective fashion, giving a broad range of β-CF3 amine precursors with a tertiary stereocentre at the β-position. This reaction
- Martinelli, Emilie,Vicini, Anna Chiara,Mancinelli, Michele,Mazzanti, Andrea,Zani, Paolo,Bernardi, Luca,Fochi, Mariafrancesca
-
supporting information
p. 658 - 660
(2015/01/09)
-
- Pesticidal compositions and processes related thereto
-
This document discloses molecules having the following formula (“Formula One”): and processes associated therewith.
- -
-
Page/Page column 45-46; 132
(2016/01/09)
-
- PESTICIDAL COMPOSITIONS AND PROCESSES RELATED THERETO
-
This disclosure relates to the field of molecules having pesticidal utility against pests in Phyla Nematoda, Arthropoda, and/or Mollusca, processes to produce such molecules and intermediates used in such processes, compositions containing such molecules, and processes of using such molecules against such pests. These molecules may be used, for example, as nematicides, acaricides, insecticides, miticides, and/or molluscicides. This document discloses molecules having the following formula (“Formula One”).
- -
-
Paragraph 0140; 0152; 0153
(2015/12/30)
-
- Diversity-oriented approach to CF3CHF-, CF3CFBr-, CF3CF2-, (CF3)2CH-, and CF3(SCF3)CH-substituted arenes from 1-(Diazo-2,2,2-trifluoroethyl)arenes
-
Arenes substituted with perfluoroalkyl groups are attractive targets for drug and agrochemical development. Exploiting the carbenic character of donor/acceptor diazo compounds, a diversity-oriented synthesis of perfluoroalkylated arenes, for late stage fluorofunctionalization, is described. The reaction of 1-(diazo-2,2,2-trifluoroethyl)arenes with HF, F/Br, F2, CF3H, and CF3SH sources give direct access to a variety of perfluoroalkyl-substituted arenes presenting with incremental fluorine content. The value of this approach is also demonstrated for radiochemistry and positron emission tomography with the [18F]-labeling of CF3CHF-, CF3CBrF-, and CF3CF2-arenes from [18F]fluoride.
- Emer, Enrico,Twilton, Jack,Tredwell, Matthew,Calderwood, Samuel,Collier, Thomas Lee,Ligault, Benot,Taillefer, Marc,Gouverneur, Vronique
-
supporting information
p. 6004 - 6007
(2015/01/09)
-
- SYNTHESIS AND USE OF FLUORINATED COMPOUNDS
-
The invention is directed to the preparation of fluorinated compounds and their use in organic synthesis. In particular, the invention is directed to methods of reacting compounds of structure with Rf-CH=N2 or (CF3)2C=N2 to form a perfluoroalkylate or -arylated compounds, and products derived from these reactions, where X, YB, and Rf are described herein.
- -
-
Paragraph 0146
(2014/09/03)
-
- PESTICIDAL COMPOSITIONS AND PROCESSES RELATED THERETO
-
This document discloses molecules having the following formula ("Formula One"): and processes associated therewith.
- -
-
Page/Page column 46; 47; 130
(2014/07/08)
-
- PESTICIDAL COMPOSITIONS AND PROCESSES RELATED THERETO
-
This document discloses molecules having the following formula (“Formula One”): and processes associated therewith.
- -
-
Paragraph 0650-0651
(2014/06/25)
-
- Nucleophilic trifluoromethylation of carbonyl compounds: Trifluoroacetaldehyde hydrate as a trifluoromethyl source
-
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.
-
p. 3300 - 3305
(2013/06/27)
-
- Highly efficient synthesis of aryl and heteroaryl trifluoromethyl ketones via o-iodobenzoic acid (IBX)
-
A two-step process for the synthesis of aryl and heteroaryl trifluoromethyl ketones from the corresponding aldehydes is described. Trifluoromethyl alcohols were prepared from aryl and heteroaryl aldehydes in excellent yields using catalytic amount of K2CO3. The trifluoromethyl alcohols were then oxidized conveniently and efficiently by o-iodoxybenzoic acid (IBX) under mild conditions to get the desired functionalized aryl and heteroaryl trifluoromethyl ketones.
- Cheng, Huicheng,Pei, Yu,Leng, Faqiang,Li, Jingya,Liang, Apeng,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
-
p. 4483 - 4486
(2013/07/26)
-
- A trifluoroacetic acid-labile sulfonate protecting group and its use in the synthesis of a near-IR fluorophore
-
Sulfonated molecules exhibit high water solubility, a property that is valuable for many biological applications but often complicates their synthesis and purification. Here we report a sulfonate protecting group that is resistant to nucleophilic attack but readily removed with trifluoroacetic acid (TFA). The use of this protecting group improved the synthesis of a sulfonated near-IR fluorophore and the mild deprotection conditions allowed isolation of the product without requiring chromatography.
- Pauff, Steven M.,Miller, Stephen C.
-
p. 711 - 716
(2013/02/25)
-
- A sterically demanding organo-superbase avoids decomposition of a naked trifluoromethyl carbanion directly generated from fluoroform
-
A simple strategy avoiding the decomposition of a naked trifluoromethyl anion to difluorocarbene by a sterically very demanding organo-superbase without the help of a trifluoromethyl anion reservoir such as DMF is reported. The direct non-metallic trifluoromethylation of carbonyl compounds using fluoroform in the presence of t-Bu-P4 base afforded trifluoromethyl alcohols in high yields.
- Kawai, Hiroyuki,Yuan, Zhe,Tokunaga, Etsuko,Shibata, Norio
-
supporting information
p. 1446 - 1450
(2013/05/09)
-
- Oxidation of α-trifluoromethyl alcohols using a recyclable oxoammonium salt
-
A simple, mild method for the oxidation of α-trifluoromethyl alcohols to trifluoromethyl ketones (TFMKs) using the oxoammonium salt 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) is described. Under basic conditions, oxidation proceeds rapidly and affords good to excellent yields of TFMKs, without concomitant formation of the hydrate. The byproduct of the oxidation, 4-acetylamino-2,2,6,6-tetramethyl-1- piperidinyloxy (1c), is easily recovered and can be conveniently reoxidized to regenerate the oxoammonium salt.
- Kelly, Christopher B.,Mercadante, Michael A.,Hamlin, Trevor A.,Fletcher, Madison H.,Leadbeater, Nicholas E.
-
p. 8131 - 8141
(2013/01/15)
-
- PESTICIDAL COMPOSITIONS AND PROCESSES RELATED THERETO
-
This document discloses molecules having the following formula (“Formula One”): and processes associated therewith.
- -
-
Page/Page column 71
(2013/02/28)
-
- Dynamics for reactions of ion pairs in aqueous solution: Reactivity of tosylate anion ion paired with the highly destabilized 1-(4-methylphenyl)-2,2,2- trifluoroethyl carbocation
-
The sum of the rate constants for solvolysis and scrambling of carbon bridging and nonbridging oxygen-18 at 4-MeC6H4CH(CF 3)OS(18O2)Tos in 50/50 (v/v) trifluoroethanol/water, (ksolvRki
- Teshima, Minami,Tsuji, Yutaka,Richard, John P.
-
experimental part
p. 730 - 734
(2011/05/06)
-
- Nonenzymatic kinetic resolution of racemic 2,2,2-trifluoro-1-aryl ethanol via enantioselective acylation
-
Kinetic resolution of a series of 2,2,2-trifluoro-1-aryl ethanol with (R)-benzotetramisole as the catalyst has been investigated. The result showed that when the aryl group in the substrate was a phenyl (or a phenyl substituted by an electron-donating group) or a naphthyl (an extended phenyl) group, the system could give an s value higher than 20. Preparative KR examples demonstrated the applicability of this method in the preparation of some of enantiomerically pure 2,2,2-trifluoro-1-aryl ethanol or 2,2,2-trifluoro-1-aryl-ethyl iso-butyrate.
- Xu, Qing,Zhou, Hui,Geng, Xiaohong,Chen, Peiran
-
supporting information; experimental part
p. 2232 - 2238
(2009/07/11)
-
- METHODS OF TREATING SEROTONIN-MEDIATED DISEASES AND DISORDERS
-
Methods are disclosed for treating serotonin-mediated diseases and disorders, which comprise inhibiting tryptophan hydroxylase (TPH) in patients in need thereof.
- -
-
-
- METHODS OF USING AND COMPOSITIONS COMPRISING TRYPTOPHAN HYDROXYLASE INHIBITORS
-
Methods and compositions comprising tryptophan hydroxylase inhibitors are disclosed. Particular methods are directed at reducing or avoiding serotonin-mediated adverse effects associated with some drugs.
- -
-
-
- METHODS OF AFFECTING GASTROINTESTINAL TRANSIT AND GASTRIC EMPTYING, AND COMPOUNDS USEFUL THEREIN
-
Methods and compounds are disclosed for affecting gastrointestinal motility and gastric emptying, which comprise inhibiting tryptophan hydroxylase (TPH) in patients in need thereof.
- -
-
-
- Multicyclic amino acid derivatives and methods of their use
-
Compounds of formulae I and II are disclosed, as well as compositions comprising them and methods of their use to treat, prevent and manage serotonin-mediated diseases and disorders:
- -
-
Page/Page column 24
(2010/11/28)
-
- Reduction of 2,2,2-trifluoro-1-arylethanones with alkyl phosphines
-
In the presence of alkyl phosphines, reduction of 2,2,2-trifluoro-1-arylethanones proceeded smoothly to give the corresponding reduction products in moderate to high yields at room temperature. The possible mechanism was discussed on the basis of deuteriu
- Shi, Min,Liu, Xu-Guang,Guo, Ying-Wen,Zhang, Wen
-
p. 12731 - 12734
(2008/03/15)
-
- Trifluoromethylation of carbonyl compounds with sodium trifluoroacetate
-
In the presence of copper(I) iodide as catalyst, a variety of carbonyl compounds, such as aldehydes, ketones and acid anhydrous, could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields, and a possible mechanism was proposed to explain the roles of catalyst and solvent in the reaction system.
- Chang, Ying,Cai, Chun
-
p. 937 - 940
(2007/10/03)
-
- Sodium trifluoroacetate: An efficient precursor for the trifluoromethylation of aldehydes
-
In a convenient and efficient procedure, the nucleophilic trifluoromethylation of aldehydes with sodium trifluoroacetate was achieved, using copper(I) halides as the catalyst.
- Chang, Ying,Cai, Chun
-
p. 3161 - 3164
(2007/10/03)
-
- Some studies on nucleophilic trifluoromethylation using the shelf-stable trifluoromethylacetophenone-N,N-dimethyltrimethylsilylamine adduct
-
The simple thermal addition product of N,N-dimethyltrimethylsilylamine with 2,2,2-trifluoroacetophenone provides a shelf-stable reagent for nucleophilic trifluoromethylation of both the carbonyl and the imine group.
- Motherwell, William B.,Storey, Lynda J.
-
p. 491 - 498
(2007/10/03)
-
- Chemoselective reduction of ketones: Trifluoromethylketones versus methylketones
-
Treatment of an equimolar mixture of trifluoromethylketones (TFMKs) and methylketones (MKs) with Et2Zn resulted in selective reduction of the TFMKs in good yield. In contrast, treatment of an equimolar mixture of TFMKs and MKs with NaBH4 in the presence of CeCl3 in EtOH/H 2O (10:1) at -10°C reduced only the MKs.
- Sasaki, Shigeru,Yamauchi, Takayasu,Kubo, Hajime,Kanai, Masatomi,Ishii, Akihiro,Higashiyama, Kimio
-
p. 1497 - 1500
(2007/10/03)
-
- The trifluoromethylacetophenone-N,N-dimethyltrimethylsilylamine adduct - A new shelf stable reagent for nucleophilic trifluoromethylation
-
The simple thermal addition product of N,N-dimethyltrimethylsilylamine with trifluoromethylacetophenone provides a shelf-stable reagent for nucleophilic trifluoromethylation of the carbonyl group.
- Motherwell, William B.,Storey, Lynda J.
-
p. 646 - 648
(2007/10/03)
-
- Coupling of fluoroform with aldehydes using an electrogenerated base
-
Trifluoromethylated alcohols are easily obtained in a one pot electroreaction in which cathodic reduction of iodobenzene generates a strong base which deprotonates fluoroform, inducing its coupling with aldehydes.
- Barhdadi, Rachid,Troupel, Michel,Perichon, Jacques
-
p. 1251 - 1252
(2007/10/03)
-
- Mechanisms of decomposition of (Z)-2,2,2-trifluoro-1-arylethanediazoates in aqueous media
-
A study of the kinetics of decay of three (Z)-2,2,2-trifluoro-1-arylethanediazoates at 25°C in aqueous media, 4% 2-propanol by volume, ionic strength 1 M (NaClO4) in the pH range 4-13, as well as the results of experiments to detect deuterium incorporation into products from solvent is reported. It is concluded in the case of the unsubstituted compound that the buffer-independent reaction involves rate-limiting heterolytic bond fission of the diazoic acid to yield a diazonium ion intermediate, and a similar mechanism is indicated for the other two compounds. General acid catalysis of the decay of the diazoic acids at pH 7 is observed, and it is concluded that the reaction involves rate-limiting N-O bond cleavage of the diazoic acid that is concerted with protonation of the leaving hydroxide ion by the catalyst.
- Finneman, Jari I.,Fishbein, James C.
-
p. 7134 - 7138
(2007/10/03)
-
- Reactions of Trifluoromethyl Bromide and Related Halides: Part 9. Comparison between Additions to Carbonyl Compounds, Enamines, and Sulphur Dioxide in the Presence of Zinc
-
A Barbier procedure, under moderate pressure, was used for the trifluoromethylation of various carbonyl compounds, starting from trifluoromethyl bromide and zinc in pyridine.Trifluoromethyl methanols were obtained from aldehydes and trifluoromethyl ketones from activated esters.Ethyl benzoate, or acetone, induced the formation of the solvated trifluoromethylzinc derivatives which did not react with carbonyl cpompounds.Consequently, the Barbier condensation in that case was considered to involve nascent organometallics reacting near the zinc surface.The reaction with sulphur dioxide, leading to trifluoromethanesulphinate, showed striking differences from that of carbonyl compounds.It was shown that the main pathway occcured in solution.This condensation was interpreted by the initial formation of sulphur dioxide radical anion, which reacts with trifluoromethyl bromide by a single-electron-transfer process.Attempts to condense iminium salts failed when a hydrogen atom was lacking in the α position.When the iminium ion can be transformed in situ to an enamine, a reaction occured, leading to α-trifluoromethyl ketones.This condensation was interpreted by a chain mechanism involving trifluoromethyl radicals.
- Tordeux, Marc,Francese, Catherine,Wakselman, Claude
-
p. 1951 - 1957
(2007/10/02)
-
- PALLADIUM AND NICKEL-CATALYZED PERFLUOROALKYLATION OF ALDEHYDES USING ZINC AND PERFLUOROALKYL HALIDES
-
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
-
p. 517 - 520
(2007/10/02)
-
- Solvolysis of 1-Aryl-2,2,2-trifluoroethyl Sulfonates. Kinetic and Stereochemical Effects in the Generation of Highly Electron-Deficient Carbocations
-
Solvolysis rates of sulfonates XC6H4CH(O3SR)CF3 (R = p-Tol or CF3) correlate with ?+(X) with values of ρ+ between -6.7 and -11.9 depending upon solvent.For the tosylates the rates depend on the solvent parameter YOTs with
- Allen, Annette D.,Ambidge, I. Christopher,Che, Claudius,Micheal, Hany,Muir, Ronald J.,Tidwell, Thomas T.
-
p. 2343 - 2350
(2007/10/02)
-
- The reduction of aryl trifluoromethyl ketones by sodium borohydride. The hydride transfer process
-
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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