- Electrochemical synthesis and structural characterisation of cadmium and mercury complexes containing pyrimidine-2-thionate ligands
-
The electrochemical oxidation of anodic metal (cadmium or mercury) in a cell containing an acetonitrile solution of the appropriate pyrimidine-2-thione (RpymSH) affords complexes [M(RpymS)2] (M = Cd, Hg; R = 4-CF 3, 4,6-CF3,Me and 4,6-CF3,Ph). When 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) was added to the electrolytic cell, adducts of cadmium and compounds with these coligands were obtained. All the compounds have been characterised by microanalysis, IR spectroscopy and, in the case of the compounds that were sufficiently soluble, by 1H, 13C and 199Hg NMR spectroscopy. The compounds [Cd(4-CF3pymS)2] (1), [Cd(4,6-CF 3MepymS)2(bipy)] (4), [Cd(4,6-CF3PhpymS) 2 (phen)] (6) and [Hg(4,6-CF3MepymS)2] (8) were also characterised by X-ray diffraction. Compound 1 presents a polymeric structure with the polymer chains interconnected by intermolecular C-H...N interactions. Compounds 4 and 6 adopt mononuclear structures, with weak inter- and intra-molecular C-H...π interactions, as well as π-π stacking interactions for compound 6. Compound 8 also presents a mononuclear structure with intermolecular π-π interactions between the pyrimidine rings and additional weak Hg...Hg contacts (3.484 A). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Rodriguez, Antonio,Sousa-Pedrares, Antonio,Garcia-Vazquez, Jose A.,Romero, Jaime,Sousa, Antonio
-
-
Read Online
- HETEROCYCLIC COMPOUNDS AS ANTI-VIRAL AGENTS
-
The present invention discloses compounds of Formula (I), or pharmaceutically acceptable salts, esters, or prodrugs thereof: which inhibit Respiratory Syncytial Virus (RSV) or HMPV. The present invention further relates to pharmaceutical compositions comp
- -
-
Page/Page column 47
(2021/07/31)
-
- Radical Trifluoroacetylation of Alkenes Triggered by a Visible-Light-Promoted C–O Bond Fragmentation of Trifluoroacetic Anhydride
-
We report a mild and operationally simple trifluoroacylation strategy of olefines, that utilizes trifluoroacetic anhydride as a low-cost and readily available reagent. This light-mediated process is fundamentally different from conventional methodologies and occurs through a trifluoroacyl radical mechanism promoted by a photocatalyst, which triggers a C?O bond fragmentation. Mechanistic studies (kinetic isotope effects, spectroelectrochemistry, optical spectroscopy, theoretical investigations) highlight the evidence of a fleeting CF3CO radical under photoredox conditions. The trifluoroacyl radical can be stabilized under CO atmosphere, delivering the trifluoroacetylation product with higher chemical efficiency. Furthermore, the method can be turned into a trifluoromethylation protocol by simply changing the reaction parameters. Beyond simple alkenes, this method allows for chemo- and regioselective functionalization of small-molecule drugs and common pharmacophores.
- Jeschke, Gunnar,Katayev, Dmitry,N?tel, Nicolas Yannick,Rombach, David,Zhang, Kun
-
supporting information
p. 22487 - 22495
(2021/09/09)
-
- Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system
-
A straightforward method that enables the formation of biologically attractive trifluoromethyl ketones from readily available methyl esters using the potent greenhouse gas fluoroform (HCF3, HFC-23) was developed. The combination of fluoroform and KHMDS in triglyme at ?40 °C was effective for this transformation, with good yields as high as 92%. Substrate scope of the trifluoromethylation procedure was explored for aromatic, aliphatic, and conjugated methyl esters. This study presents a straightforward trifluoromethylation process of various methyl esters that convert well to the corresponding trifluoromethyl ketones. The tolerance of various pharmacophores under the reaction conditions was also explored.
- Fujihira, Yamato,Liang, Yumeng,Ono, Makoto,Hirano, Kazuki,Kagawa, Takumi,Shibata, Norio
-
supporting information
p. 431 - 438
(2021/03/20)
-
- The Importance of 1,5-Oxygen???Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis
-
The importance of 1,5-O???chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O???Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram-scale synthesis of the most active selenium analogue was developed using a previously unreported seleno-Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N-acylated intermediates.
- Cockroft, Scott L.,Elmi, Alex,Frost, Aileen B.,Ling, Kenneth B.,McLaughlin, Calum,Morris, Rylie K.,Pascoe, Dominic J.,Slawin, Alexandra M. Z.,Smith, Andrew D.,Smith, Terry K.,Willoughby, Patrick H.,Woods, Andrew M.,Young, Claire M.,de la Houpliere, Alix
-
p. 3705 - 3710
(2020/02/11)
-
- Oxidation of 4-Aryl-1,1,1-trifluorobut-2-en-2-yl Trifluoro?-methanesulfonates by 4-Picoline-N-Oxide: A Novel Approach to β-Trifluoromethyl-α,β-enones
-
An efficient approach to β-trifluoromethyl-α,β-enones via oxidation of 4-aryl-1,1,1-trifluorobut-2-en-2-yl trifluoromethanesulfonates is described. The reaction proceeds smoothly under mild and metal?-free conditions and tolerates a wide range of functional groups. Various β-trifluoromethyl-α,β-enones were obtained in moderate to good yields.
- Li, Dong,Lv, Shujun,Qu, Jingping,Zhou, Yuhan
-
p. 1203 - 1210
(2020/04/15)
-
- One-Pot Sequential Multistep Transformation of α,β-Unsaturated Trifluoromethyl Ketones: Facile Synthesis of Trifluoromethylated 2-Pyridones
-
A one-pot transformation of α,β-unsaturated trifluoromethyl ketones with 2-(phenylsulfinyl)acetamide to give trifluoromethylated 2-pyridones is realized. The reaction proceeds under mild conditions and involves multiple steps in an expeditious and controlled sequence to provide efficient access to a broad range of trifluoromethylated 2-pyridones in moderate to high yields. Moreover, further synthetic manipulations permit the routine synthesis of a diverse array of trifluoromethylated pyridines with good efficiency.
- Lv, Ning,Tian, Yi-Qiang,Zhang, Fa-Guang,Ma, Jun-An
-
supporting information
p. 605 - 609
(2019/03/07)
-
- Evaluating aryl esters as bench-stable C(1)-ammonium enolate precursors in catalytic, enantioselective Michael addition-lactonisations
-
An evaluation of a range of aryl, alkyl and vinyl esters as prospective C(1)-ammonium enolate precursors in enantioselective Michael addition-lactonisation processes with (E)-trifluoromethylenones using isothiourea catalysis is reported. Electron deficient aryl esters are required for reactivity, with 2,4,6-trichlorophenyl esters providing optimal product yields. Catalyst screening showed that tetramisole was the most effective isothiourea catalyst, giving the desired dihydropyranone product in excellent yield and stereoselectivity (up to 90 : 10 dr and 98 : 2 er). The scope and limitations of this process have been evaluated, with a range of diester products being generated after ring-opening with MeOH to give stereodefined dihydropyranones with excellent stereocontrol (10 examples, typically ~90 : 10 dr and >95 : 5 er).
- Young, Claire M.,Taylor, James E.,Smith, Andrew D.
-
p. 4747 - 4752
(2019/05/24)
-
- One-Pot Catalytic Enantioselective Synthesis of 2-Pyrazolines
-
A scalable, one-pot, enantioselective catalytic synthesis of 2-pyrazolines from beta-substituted enones and hydrazines is described. Pivoting on a two-stage catalytic Michael addition/condensation strategy, the use of an aldehyde to generate a suitable hydrazone derivative of the hydrazine was found to be key for curtailing background reactivity and tuning the catalyst-controlled enantioselectivity. The new synthetic method is easy to perform, uses a new and readily prepared cinchona-derived bifunctional catalyst, is broad in scope, and tolerates a range of functionalities with high enantioselectivity (up to >99:1 e.r.). The significant scalability of this methodology was demonstrated with the synthesis of more than 80 grams of a pyrazoline product with 89 % catalyst recovery.
- Thomson, Connor J.,Barber, David M.,Dixon, Darren J.
-
p. 2469 - 2473
(2019/02/01)
-
- Enantioselective Palladium-Catalyzed [3+2] Cycloaddition of Trimethylenemethane and Fluorinated Ketones
-
A nitrile-substituted trimethylenemethane (TMM) donor undergoes palladium-catalyzed [3+2] cycloadditions with fluorinated ketones to generate tetrasubstituted trifluoromethylated centers in high enantioselectivity under mild conditions. The generation of the palladium–TMM complex was achieved by a self-deprotonation strategy, which shows remarkable improvements in regiocontrol, efficiency, and atom economy of asymmetric [3+2] cycloadditions. Moreover, the versatility of the nitrile group provides direct access to a variety of synthetically useful intermediates, including amides, aldehydes, and esters. The developed reaction conditions allow for the synthesis of a wide variety of aromatic, heteroaromatic, and aliphatic fluorinated dihydrofurans in excellent regio- and enantioselectivities.
- Trost, Barry M.,Mata, Guillaume
-
supporting information
p. 12333 - 12337
(2018/09/10)
-
- A Remarkable Influence of a Trifluoromethyl Group on the Reactions of β-Mercaptoalcohols with Fluorinated α-Bromoenones
-
Isomeric fluorinated α-bromoenones react with dinucleophilic β-mercaptoalcohols in CH2Cl2 at room temperature in the presence of Et3N in a multistep process. Depending on the position of the CF3 group, different O,S-heterocycles or non-cyclic products were obtained. With 3-bromo-1,1,1-trifluorobut-3-en-2-ones derivatives of 1,4-oxathianes were formed, but isomeric 2-bromo-4,4,4-trifluorobut-2-en-1-ones yielded 1,3-oxathiolanes or non-cyclic sulfides. The thia-Michael addition is proposed as the initial step of the reaction, and the final heterocyclization is governed by the location of the CF3 group.
- Obijalska, Emilia,Pawelec, Maria,Mlostoń, Grzegorz,Capperucci, Antonella,Tanini, Damiano,Heimgartner, Heinz
-
p. 3716 - 3723
(2018/04/09)
-
- MgCl2-catalyzed trifluoromethylation of carbonyl compounds using (trifluoromethyl)trimethylsilane as the trifluoromethylating agent
-
Using (trifluoromethyl)trimethylsilane (TMSCF3) as the trifluoromethylating agent, MgCl2-catalyzed trifluoromethylation of carbonyl compounds proceeded readily at room temperature. In the presence of 10 mol% of MgCl2, a variety of carbonyl substrates such as aliphatic/aromatic aldehydes, acyclic/cyclic ketones and esters could be trifluoromethylated in DMF, giving the corresponding trimethylsilyl ethers (ketals) in up to 93% isolated yields. Trifluoromethylketones could be readily obtained after hydrolysis of the trimethylsilyl ketals. The reactions could tolerate air and moisture, and the use of oxygen and moisture-free conditions was not required.
- Cui, Bin,Sun, Hui,Xu, Yibo,Duan, Lili,Li, Yue-Ming
-
p. 6754 - 6762
(2017/11/09)
-
- NHC-Copper(I) Halide-Catalyzed Direct Alkynylation of Trifluoromethyl Ketones on Water
-
An efficient and easily scalable NHC-copper(I) halide-catalyzed addition of terminal alkynes to 1,1,1-trifluoromethyl ketones, carried out on water for the first time, is reported. A series of addition reactions were performed with as little as 0.1-2.0?mo
- Czerwiński, Pawe?,Molga, Edyta,Cavallo, Luigi,Poater, Albert,Michalak, Micha?
-
supporting information
p. 8089 - 8094
(2016/06/13)
-
- Exploiting the Imidazolium Effect in Base-free Ammonium Enolate Generation: Synthetic and Mechanistic Studies
-
N-Acyl imidazoles and catalytic isothiourea hydrochloride salts function as ammonium enolate precursors in the absence of base. Enantioselective Michael addition–cyclization reactions using different α,β-unsaturated Michael acceptors have been performed to form dihydropyranones and dihydropyridinones with high stereoselectivity. Detailed mechanistic studies using RPKA have revealed the importance of the “imidazolium” effect in ammonium enolate formation and have highlighted key differences with traditional base-mediated processes.
- Young, Claire M.,Stark, Daniel G.,West, Thomas H.,Taylor, James E.,Smith, Andrew D.
-
supporting information
p. 14394 - 14399
(2016/11/11)
-
- Strong influence of the trifluoromethyl group on the chemoselectivity of [3+2]-cycloadditions of thiocarbonyl S-methanides with α,β-unsaturated ketones
-
The in situ-generated reactive thiocarbonyl S-methanides were reacted with fluorinated enones. The type of the obtained [3+2]-cycloadduct depends strongly on the location of the activating CF3group. In the case of enones containing the CF3
- Mlostoń, Grzegorz,Grzelak, Paulina,Heimgartner, Heinz
-
-
- Palladium-Catalyzed Trimethylenemethane Cycloaddition of Olefins Activated by the δ-Electron-Withdrawing Trifluoromethyl Group
-
α-Trifluoromethyl-styrenes, trifluoromethyl-enynes, and dienes undergo palladium-catalyzed trimethylenemethane cycloadditions under mild reaction conditions. The trifluoromethyl group serves as a unique δ-electron-withdrawing group for the activation of the olefin toward the cycloaddition. This method allows for the formation of exomethylene cyclopentanes bearing a quaternary center substituted by the trifluoromethyl group, compounds of interest for the pharmaceutical, agrochemical, and materials industries. In the diene series, the cycloaddition operates in a [3 + 4] and/or [3 + 2] manner to give rise to seven- and/or five-membered rings. This transformation greatly improves the scope of the TMM cycloaddition technology and provides invaluable insights into the reaction mechanism.
- Trost, Barry M.,Debien, Laurent
-
p. 11606 - 11609
(2015/09/28)
-
- Organocatalytic Aerobic Oxidation of α-Fluoroalkyl Alcohols to Fluoroalkyl Ketones at Room Temperature
-
The organocatalytic aerobic oxidation of electron-deficient α-fluoroalkyl alcohols at room temperature is described. The resulting fluoroalkyl ketones are versatile synthetic intermediates for a variety of fluorine-containing molecules. This otherwise difficult transformation has now been accomplished by the reaction of α-fluoroalkyl alcohols with N-oxyl radicals, catalytically generated from 9-azabicyclo[3.3.1]nonan-3-one N-oxyl/nitrogen oxide (keto-ABNO/NOx) and oxygen in acetic acid (AcOH), affording the corresponding fluoroalkyl ketones in high yield. This operationally simple reaction can be performed under mild conditions, and was applied to a wide range of alcohols (20 examples), thus demonstrating a high functional group tolerance. Moreover, a modified one-pot protocol based on this method was able to convert an aldehyde to a trifluoromethyl ketone on a gram scale.
- Kadoh, Yoichi,Tashiro, Masayuki,Oisaki, Kounosuke,Kanai, Motomu
-
p. 2193 - 2198
(2015/07/27)
-
- Highly enantioselective copper(i)-catalyzed conjugate addition of 1,3-diynes to α,β-unsaturated trifluoromethyl ketones
-
The conjugate diynylation of α,β-unsaturated trifluoromethyl ketones is carried out in the presence of a low catalytic load (2.5 mol%) of a copper(i)-MeOBIPHEP complex, triethylamine and a terminal 1,3-diyne. Pre-metalation of the terminal 1,3-diyne with stoichiometric or higher amounts of dialkylzinc reagent is not required. The corresponding internal diynes bearing a propargylic stereogenic center are obtained with good yields and excellent enantioselectivities. This journal is
- Sanz-Marco, Amparo,Blay, Gonzalo,Mu?oz, M. Carmen,Pedro, José R.
-
supporting information
p. 8958 - 8961
(2015/05/27)
-
- An efficient route to 3-trifluoromethylpyrazole via cyclization/1,5-H shift and its applications in the synthesis of bioactive compounds
-
A methodology for regioselective synthesis of 3-trifluoromethylpyrazole from the reaction of trifluoromethyl alkenone and tosylhydrazone has been developed. The reaction was proposed to proceed through a tandem cyclization and 1,5-H shift reaction, which can be applied to the synthesis of bioactive compounds like Celecoxib, Mavacoxib, and SC-560.
- Wang, Yongdong,Han, Jing,Chen, Jie,Cao, Weiguo
-
p. 8256 - 8262
(2015/10/05)
-
- Reactions of CF3-enones with arenes under superelectrophilic activation: A pathway to trans-1,3-diaryl-1-CF3-indanes, new cannabinoid receptor ligands
-
4-Aryl-1,1,1-trifluorobut-3-en-2-ones ArCHCHCOCF3 (CF3-enones) react with arenes in excess of Bronsted superacids (TfOH, FSO3H) to give, stereoselectively, trans-1,3-diaryl-1-trifluoromethyl indanes in 35-85% yields. The r
- Iakovenko, Roman O.,Kazakova, Anna N.,Muzalevskiy, Vasiliy M.,Ivanov, Alexander Yu.,Boyarskaya, Irina A.,Chicca, Andrea,Petrucci, Vanessa,Gertsch, Jürg,Krasavin, Mikhail,Starova, Galina L.,Zolotarev, Andrey A.,Avdontceva, Margarita S.,Nenajdenko, Valentine G.,Vasilyev, Aleksander V.
-
p. 8827 - 8842
(2015/08/24)
-
- New methodology toward α,β-unsaturated carboxylic acids from saturated acids
-
A carefully designed three-step unsaturation of carboxylic acids is described. Briefly, carboxylic acids were converted to the trifluoromethyl ketone. Subsequent treatment with selenium dioxide followed by hydrolysis afforded α,β-unsaturated carboxylic acids. The mechanism of the reported transformation was investigated, which led us to propose a novel explanation featuring selenium dioxide assisted enolizaion of a trifluoromethyl ketone followed by β-deprotonation.
- Li, Qingjiang,Tochtrop, Gregory P.
-
supporting information
p. 1382 - 1385
(2014/04/03)
-
- Asymmetric synthesis of tri- and tetrasubstituted trifluoromethyl dihydropyranones from α-aroyloxyaldehydes via NHC redox catalysis
-
The asymmetric synthesis of tri- and tetrasubstituted trifluoromethyl dihydropyranones via an NHC-catalyzed redox process, introducing methyl, benzyl, and aryl substituents to the C(5) position, is presented. Their substrate-controlled derivatization into
- Davies, Alyn T.,Pickett, Philip M.,Slawin, Alexandra M.Z.,Smith, Andrew D.
-
p. 2696 - 2700
(2014/08/18)
-
- Isothiourea-mediated one-pot synthesis of trifluoromethyl substituted 2-pyrones
-
A one-pot isothiourea-mediated Michael addition/lactonization/thiol elimination cascade sequence for the formation of 4,6-disubstituted and 3,4,6-trisubstituted 2-pyrones from (phenylthio)acetic acids and α,β-unsaturated trifluoromethyl ketones is described. The synthesis of a COX-2 inhibitor and the wide-ranging derivatization of the 2-pyrone moiety to trifluoromethyl substituted aromatics and heteroaromatics is also disclosed.
- Yeh, Pei-Pei,Daniels, David S. B.,Cordes, David B.,Slawin, Alexandra M. Z.,Smith, Andrew D.
-
supporting information
p. 964 - 967
(2014/03/21)
-
- 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)
-
- Dehydrogenation of perfluoroalkyl ketones by using a recyclable oxoammonium salt
-
A novel dehydrogenation reaction of perfluoroalkyl ketones by the oxoammonium salt 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (4-NHAc-TEMPO+BF4-, Bobbitt's salt, 1) is described. The reaction proceeds under mildly basic conditions and appears to be unique to perfluoroalkyl ketones. A proposed mechanism for this unusual transformation is given. The byproduct of the reaction, 4-acetylamino-2,2,6,6-tetramethyl-1-piperidinyloxy (1a), can easily be recovered and used to regenerate the oxoammonium salt. The dehydrogenation of perfluoroalkyl ketones by using an oxoammonium salt is reported. The reaction proceeds under mildly basic conditions and affords α,β-unsaturated products in fair to excellent yields. The reaction likely proceeds through a two-step sequence. The spent oxidant can easily be recovered and used to regenerate the oxoammonium salt. Copyright
- Hamlin, Trevor A.,Kelly, Christopher B.,Leadbeater, Nicholas E.
-
p. 3658 - 3661
(2013/07/19)
-
- Microwave-assisted convenient synthesis of α,β-unsaturated esters and ketones via aldol-adduct elimination
-
Various fluorinated 3-oxo ester/1,3-diketones were reacted with carbonyl compounds, in presence of piperidine and under microwave irradiation, to afford (E)-α,β-unsaturated esters and ketones in good yields. The systematic study reveals that the reaction proceeded through the formation of aldol adduct. The method provides a new and simple way for C,C bond formations. Copyright
- Suman, Pathi,Nageswara Rao, Rayala,China Raju, Bhimapaka
-
p. 1548 - 1559
(2013/09/02)
-
- 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)
-
- A Weinreb amide approach to the synthesis of trifluoromethylketones
-
A novel route to access trifluoromethylketones (TFMKs) from Weinreb amides is reported. This represents the first documented case of the Ruppert-Prakash reagent (TMS-CF3) reacting in a constructive manner with an amide and enables synthesis of TMFKs without risk of over-trifluoromethylation.
- Rudzinski, Diandra M.,Kelly, Christopher B.,Leadbeater, Nicholas E.
-
supporting information
p. 9610 - 9612
(2012/10/29)
-
- A new entry for the oxidation of fluoroalkyl-substituted methanol derivatives: Scope and limitation of the organoiodine(V) reagent-catalyzed oxidation
-
Oxidation of various fluoroalkyl-substituted methanol derivatives under the influence of a catalytic amount of sodium 2-iodobenzenesulfonate and Oxone in CH3CN or CH3NO2 was investigated in detail. The efficiency of the newly developed oxidation was also evaluated by comparison to other oxidations, such as Dess-Martin, PDC, and Swern oxidation.
- Tanaka, Yusuke,Ishihara, Takashi,Konno, Tsutomu
-
experimental part
p. 99 - 104
(2012/05/07)
-
- Highly efficient asymmetric epoxidation of electron-deficient α,β-enones and related applications to organic synthesis
-
The asymmetric epoxidation of electrondeficient olefins has been achieved using inexpensive and readily available prolinols as catalysts with good to excellent yields and enantioselectivities. The utility of the resulting chiral epoxides was illustrated b
- Zheng, Changwu,Li, Yawen,Yang, Yingquan,Wang, Haifeng,Cui, Haifeng,Zhang, Junkang,Zhao, Gang
-
supporting information; experimental part
p. 1685 - 1691
(2011/02/25)
-
- Silver compounds in synthetic chemistry. Part 5: Selective syntheses of trifluoromethylketones, RCOCF3, from trifluoromethylsilver, AgCF3, and corresponding acyl chlorides, RCOCl
-
Trifluoromethylketones of aromatics, heteroaromatics and olefins are formed selectively from reactions of trifluoromethylsilver and the corresponding carboxylic acid chlorides in moderate to excellent yields. The conditions chosen are dependent on the nature of the acyl chloride. Attempts to prepare alkyl(trifluoromethyl)ketones yielded product mixtures of the corresponding acyl fluorides, trifluoromethyl-, pentafluoroethyl- and n-heptafluoropropyl ketones.
- Kremlev, Mikhail M.,Mushta, Aleksej I.,Tyrra, Wieland,Naumann, Dieter,Fischer, Hendrik T.M.,Yagupolskii, Yurii L.
-
p. 1385 - 1389
(2008/09/18)
-
- Reaction of 1,2-unsaturated trifluoromethyl ketones and their conversion to 1-(trifluoromethyl)furan derivatives
-
A novel synthetic approach leading to 1-(trifluoromethyl)furan derivatives is reported. 4-Aryl-1,1,1-trifluorobut-3-en-2-one was iodinated and subsequently reduced to give the corresponding alcohol. The resultant iodo compound was then subjected to coupli
- Zhang, Dehui,Yuan, Chengye
-
p. 3916 - 3924
(2008/02/13)
-
- Lewis base-catalyzed perfluoroalkylation of carbonyl compounds and imines with (perfluoroalkyl)trimethylsilane
-
Lewis base-catalyzed perfluoroalkylation of carbonyl compounds and aldimines with (perfluoroalkyl)trimethylsilanes (TMSCF3, TMSC 2F5, and TMSC3F7) is described. The nitrogen- or oxygen-containing anions generated from amides, imides, and carboxylic acids have been found to work as effective Lewis-base catalysts in perfluoroalkylation that proceeds via activation of the carbon-silicon bonds of (perfluoroalkyl)trimethylsilanes. Reactions of carbonyl compounds such as aldehydes, ketones, and esters with TMSCF3 in the presence of a catalytic amount of Lewis bases proceeded smoothly to afford the corresponding adducts in good-to-high yields under mild conditions. Although it was considered difficult, this catalytic perfluoroalkylation of various aldimines with (perfluoroalkyl)trimethylsilane in the presence of Lewis bases such as lithium acetate or benzoate proceeded efficiently to give the corresponding perfluoroalkylated adducts, because the aldimines here were weak electrophiles toward (perfluoroalkyl)trimethylsilanes. The present reaction is, therefore, the first example of a catalytic perfluoroalkylation of aldimines.
- Kawano, Yoshikazu,Kaneko, Nobuya,Mukaiyama, Teruaki
-
p. 1133 - 1145
(2007/10/03)
-
- Enantioselective reduction of α,β-unsaturated ketones bearing the trifluoromethyl group
-
α,β-Unsaturated ketones bearing the trifluoromethyl group were enantioselectively reduced by a variety of reagents to the corresponding secondary allylic alcohols with e.e. in the range 87-99%. The influence of the trifluoromethyl group on the enantioselectivity is discussed.
- Nenajdenko, Valentine G.,Smolko, Konstantin I.,Balenkova, Elizabeth S.
-
p. 1259 - 1266
(2007/10/03)
-
- A facile stereocontrolled synthesis of anti-alpha-(trifluoromethyl)-beta-amino alcohols.
-
A short stereocontrolled preparation of anti-alpha-(trifluoromethyl)-beta-amino alcohols is described, involving an initial CF(3) transfer to cinnamaldehyde and a one-step, three-component condensation of 3,3,3-trifluorolactic aldehyde, an alkenyl (aryl)
- Prakash,Mandal,Schweizer,Petasis,Olah
-
p. 3173 - 3176
(2007/10/03)
-
- Synthesis of αβ-unsaturated trifluoromethyl ketones from 4-Dimethylamino-1,1,1-trifluorobut-3-ene-2-one by addition of grignard reagents
-
Enaminones are available by reaction of 4-ethoxy-1,1,1-trifluorobut-3-ene-2-one with amines such as dimethylamine and they react with Grignard reagents to give αβ-unsaturated trifluoromethyl ketones in good yield by 1,4-addition followed by elimination. The generality of this procedure is contrasted with reactions based either on the use of organolithium nucleophiles, or the use of 4-alkoxy-αβ-unsaturated trifluoromethyl ketones as electrophilic partners. (C) 2000 Elsevier Science Ltd.
- Andrew, Rebecca J.,Mellor, John M.
-
p. 7261 - 7266
(2007/10/03)
-
- Cesium fluoride catalyzed trifluoromethylation of esters, aldehydes, and ketones with (trifluoromethyl)trimethylsilane
-
The low reactivity of carboxylic esters toward (trifluoromethyl)trimethylsilane (TMS-CF3) was investigated. A universal cesium fluoride catalyzed procedure for nucleophilic trifluoromethylation was developed. At room temperature (25 °C, with catalytic amounts of cesium fluoride, carboxylic esters were found to react to give the silyl ether intermediates, which afforded the trifluoromethyl ketones after hydrolysis. Sulfonic, sulfinic, and selenic esters also show good reactivity, giving novel trifluoromethylated compounds. The trifluoromethylation method was also applied to aldehydes and ketones, which were transformed to trifluoromethyl silyl ether intermediates and afforded trifluoromethylated alcohols in excellent yields after acid hydrolysis. Ethylene glycol dimethyl ether was used as solvent for solid or high boiling substrates, and benzonitrile was used for the low boiling substrates.
- Singh, Rajendra P.,Cao, Ganfeng,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
-
p. 2873 - 2876
(2007/10/03)
-
- Synthesis and stereochemistry of trifluoromethyl-containing isoxazolidines
-
The reaction of trifluoromethyl-containing enones with hydroxylamine under various conditions is studied. The products in basic medium are equilibrating mixtures of isoxazolidine diastereomers in an ~1:1 ratio. The energy of the nitrogen atom inversion ba
- Nenajdenko,Sanin,Tok,Balenkova
-
p. 348 - 357
(2007/10/03)
-
- Direct preparation of trifluoromethyl ketones from carboxylic esters: Trifluoromethylation with (trifluoromethyl)trimethylsilane
-
Previously difficult to prepare, alipathic and alicyclic trifluoromethylketones (e.g. 1 and 2), which are of pharmacologic interest as potential enzyme inhibitors, can now be synthesized easily and efficiently. The one-step reaction starting with carbonic esters and trimethyl(trifluoromethyl)silane is induced by tetrabutylammonium fluoride in nonpolar, aprotic solvents and proceeds without formation of double-addition products.
- Wiedemann, Juergen,Heiner, Thomas,Mloston, Gregorz,Prakash, G.K. Surya,Olah, George A.
-
p. 820 - 821
(2007/10/03)
-
- A convenient one-pot synthesis of 6-trifluoromethyl-pyridines
-
α,β-Unsaturated trifluoromethyl ketones (1) react with primary enamines (2) such as β-aminocrotononitrile and β-aminocrotonates in the presence of phosphorus oxychloride / pyridine adsorbed on silica gel and manganese dioxide, providing good to high yield
- Katsuyama, Isamu,Ogawa, Seiya,Nakamura, Hiroko,Yamaguchi, Yoshihiro,Funabiki, Kazumasa,Matsui, Masaki,Muramatsu, Hiroshige,Shibata, Katsuyoshi
-
p. 779 - 785
(2007/10/03)
-
- Oxidation of fluoroalkyl-substituted allylic alcohols: A synthesis of fluorinated α,β-epoxyketones
-
Fluoroalkyl-substituted allylic alcohols are readily and selectively oxidized at the hydroxyl group with the Swern or Dess-Martin reagents to give α,β-unsaturated ketones, and on treatment with m-chloroperbenzoic acid or tert-butyl hydroperoxide they are oxidized to the corresponding epoxyalcohols. The latter are oxidized by Swern or Dess-Martin reagents at the hydroxyl group to α,β-epoxyketones, which form hydrates stable under the conditions of isolation.
- Ratner,Pashkevick
-
p. 640 - 644
(2007/10/03)
-
- A new and convenient one-pot synthesis of α,β-unsaturated trifluoromethyl ketones
-
Alkylphosphonates react with N-phenyltrifluoroacetimidoyl chloride in the presence of lithium diisopropylamide to afford mixtures which when treated with aldehydes and subjected to acid hydrolysis afford α,β-unsaturated trifluoromethyl ketones.
- Huang, Wei Sheng,Yuan, Cheng Ye
-
p. 741 - 742
(2007/10/02)
-
- Synthesis of α,β-Unsaturated Ketones Containing a Perfluorinated Group
-
Acylation of various alkenes with trifluoroacetic anhydride in the presence of the dimethyl sulfide-boron trifluoride complex yields corresponding unsaturated ketones with a perfluoroacyl moiety.The effect of the substrate structure on the reaction direct
- Nenaidenko, V. G.,Balenkova, E. S.
-
p. 1030 - 1036
(2007/10/03)
-
- Perfluoroacylation of alkenes
-
Reaction of direct electrophilic perfluoroacylation of different structure alkenes with trifluoroacetic anhydride activated by BF3·SMe2 complex leads to trifluoromethylalkenylketones with different structure of alkenyl group. Possibl
- Nenajdenko, Valentine G.,Gridnev, Ilya D.,Balenkova, Elizabeth S.
-
p. 11023 - 11038
(2007/10/02)
-
- The interaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one with C-nucleophiles - organo-magnesium and -zinc compounds
-
4-Ethoxy-1,1,1-trifluoro-3-buten-2-one (1) reacts with phenylmagnesium bromide to give ethoxy group substitution products while the reaction of 1 with organozinc compounds gives products arising from 1,2-addition to the carbonyl group.Enone 1 reacts with electron-rich aromatic systems such as indole and N,N-dimethylaniline in the presence of a Lewis acid catalyst to give a β-arylvinyltrifluoromethylketone.
- Gorbunova, M. G.,Gerus, I. I.,Kukhar, V. P.
-
-
- Fluorinated Retinoids via Crossed Aldol Condensation of 1,1,1-Trifluoroacetone
-
Piperidine-acetic acid catalyzed crossed aldol condensation of 1,1,1-trifluoroacetone with aryl or α,β-unsaturated aldehydes was found to be a useful method for the preparation of unsaturated trifluoromethyl ketones.Chain extension of these ketones led to several new fluorinated retinoids including the hitherto elusive all-trans isomers of 19,19,19- and 20,20,20-trifluororetinal.
- Mead, Dennis,Loh, Rhonda,Asato, A. E.,Liu, R. S. H.
-
p. 2873 - 2876
(2007/10/02)
-
- Methyl vs. Methylene Condensation of Aromatic Aldehydes with 1,1,1-Trifluoroacetylacetone
-
From the slow Knoevenagel condensations of 1,1,1-trifluoroacetylacetone (4) with aromatic aldehydes in benzene in the presence of piperidine-AcOH, low yields of three products were isolated: the enol form of the methyl-condensation product ArCH=CHCOCH=C(O
- Gazit, Aviv,Rappoport, Zvi
-
p. 2863 - 2870
(2007/10/02)
-
- NOVEL SYNTHESIS OF F-1-ALKENE-1-PHOSPHONATE DERIVATIVES FROM F-ALKANOYL CHLORIDES AND THEIR EFFICIENT USE FOR PREPARING FLUORO-α,β-ENONES
-
(Z)-1--F-1-alkene-1-phosphonates were synthesized in good yields from F-alkanoyl chlorides and triethyl phosphite, and were proved to be useful precursors for the preparation of fluoro-α,β-enones.
- Ishihara, Takashi,Maekawa, Takashige,Ando, Teiichi
-
p. 4229 - 4232
(2007/10/02)
-