- Synthesis of (Z)-α-Trifluoromethyl Alkenyl Triflate: A Scaffold for Diverse Trifluoromethylated Species
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An efficient method for the synthesis of (Z)-selective α-trifluoromethyl alkenyl triflates is described. As an important fluorinated building block, it is utilized successfully for the synthesis of various trifluoromethyl derivatives such as diarylethylen
- Zhao, Yilong,Zhou, Yuhan,Liu, Juan,Yang, Dongmei,Tao, Liang,Liu, Yang,Dong, Xiaoliang,Liu, Jianhui,Qu, Jingping
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p. 4797 - 4806
(2016/07/06)
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- Wittig Reactions of Phosphonium Ylides Bearing the Phosphastibatriptycene Skeleton with Carbonyl Compounds
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To investigate effects of the tridentate ligand on the reactivity of a 1,2-oxaphosphetane, an intermediate of the Wittig reaction, the reactions of phosphonium ylides 1 and 2 bearing the phosphastibatriptycene skeleton with carbonyl compounds have been conducted and compared with those of triphenyl phosphorus compounds. Non-stabilized and semi-stabilized phosphonium ylides 1 and 2 bearing the tridentate ligand were generated from the corresponding phosphonium salts 3 and 4, which were prepared by the reactions of a phosphastibatriptycene with ethyl iodide and benzyl bromide, respectively. The reactions of ylides 1 and 2 with benzaldehyde showed high E-selectivity, in sharp contrast to those of triphenylphosphonium ylides 5 and 6 giving Z-alkenes as a major product. However, the reaction of 1 with trifluoroacetophenone gave E/Z-alkenes 10 in the ratio of 69:31 together with phosphine oxide 13, which showed slightly higher selective E-alkene formation compared with the reaction of non-stabilized ylide 5 (E/Z ratio of 51:49). The results showed that the reactions did not proceed with high stereoselectivity as same as those of semi-stabilized phosphonium ylides 2 and 6. In the VT-31P{1H} NMR spectra of the reaction mixture of non-stabilized phosphonium ylide 1 with trifluoroacetophenone, the signals due to the corresponding 1,2-oxaphosphetanes were observed as multi signals in high field around -54 ppm at -80°C, which was different from the reaction of ylide 5 showing two signals.
- Uchiyama, Yosuke,Murakami, Rikiya,Sugimoto, Jun
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p. 633 - 637
(2016/01/15)
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- Pd-carbene migratory insertion: Application to the synthesis of trifluoromethylated alkenes and dienes
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Pd-catalyzed cross-coupling of halides with CF3-substituted diazo compounds or N-tosylhydrazones has been explored for the synthesis of CF3-substituted alkenes and 1,3-butadienes. Pd-carbene migratory insertion plays the key role in these transformations. Copyright
- Wang, Xi,Xu, Yan,Deng, Yifan,Zhou, Yujing,Feng, Jiajie,Ji, Guojing,Zhang, Yan,Wang, Jianbo
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supporting information
p. 961 - 965
(2014/02/14)
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- One-pot multistep synthesis of trisubstituted alkenes from N -tosylhydrazones and alcohols
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A one-pot procedure for the synthesis of trisubstituted alkenes from N-tosylhydrazones and alcohols is reported. This procedure combines the aerobic oxidation reaction and Wittig reaction in one pot, which avoids using of environmentally toxic oxidants and isolation of the intermediates. The simple procedure makes it very attractive for the synthesis of trisubstituted alkenes when alcohols are used as starting materials. A variety of trisubstituted alkenes as well as trifluoromethyl-substituted alkenes were obtained in moderate to good yields (up to 84%) with good E-selectivity (up to 99%). Georg Thieme Verlag Stuttgart.New York.
- Sha, Qiang,Wei, Yunyang
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p. 2353 - 2361
(2014/11/08)
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- Copper(i)-catalyzed wittig olefination reactions of N-tosylhydrazones with trifluoromethylketones
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Cuprous iodide-catalyzed Wittig olefination reactions of N-tosylhydrazones with trifluoromethylketones are reported. This procedure provides an efficient method for the synthesis of various trifluoromethyl-substituted alkenes in moderate to good yields (up to 89 % yield) and good stereoselectivity (up to 93 % E-selectivity). To the best of our knowledge, it is the first report of a Wittig reaction of N-tosylhydrazones with ketones. Copyright
- Sha, Qiang,Wei, Yunyang
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p. 131 - 134
(2014/01/23)
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- A convenient and mild chromatography-free method for the purification of the products of Wittig and Appel reactions
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A mild method for the facile removal of phosphine oxide from the crude products of Wittig and Appel reactions is described. Work-up with oxalyl chloride to generate insoluble chlorophosphonium salt (CPS) yields phosphorus-free products for a wide variety of these reactions. The CPS product can be further converted into phosphine.
- Byrne, Peter A.,Rajendran, Kamalraj V.,Muldoon, Jimmy,Gilheany, Declan G.
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p. 3531 - 3537
(2012/05/20)
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- Efficient trifluoromethylation of activated and non-activated alkenyl halides by using (trifluoromethyl)trimethylsilane
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An efficient method for the trifluoromethylation of halogenated double bonds by using in situ generated "trifluoromethyl copper" is described. Herein, the most common trifluoromethyl source, (trifluoromethyl) trimethylsilane, was converted selectively int
- Hafner, Andreas,Braese, Stefan
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supporting information; experimental part
p. 3044 - 3048
(2012/01/02)
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- Synthesis of gem-difluoroalkenes via β-fluoride elimination of organorhodium(I)
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Treatment of α-(trifluoromethyl)styrenes with arylboronic esters and MeMgCl in the presence of a rhodium(I) catalyst affords gem-difluoroalkenes. The reaction proceeds through the addition of arylrhodium(I) species across the electron-deficient carbon-carbon double bond and the subsequent β-fluoride elimination. Copyright
- Miura, Tomoya,Ito, Yoshiteru,Murakami, Masahiro
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scheme or table
p. 1006 - 1007
(2009/04/06)
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- Highly regio- and stereoselective hydrometallation reactions of fluorine-containing internal alkynes: Novel approaches to fluoroalkylated alkenes
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Hydroalumination, hydrocupration, and hydroboration reactions of various fluorine-containing alkynes were investigated. The alkyne reacted smoothly with 2.0 equiv. of Red-Al at -78°C to give the hydroaluminated adduct in a highly regio- and stereoselectiv
- Konno, Tsutomu,Chae, Jungha,Tanaka, Tomoo,Ishihara, Takashi,Yamanaka, Hiroki
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- Syntheses, structures, and thermolyses of pentacoordinate 1,2-oxastibetanes: Potential intermediates in the reactions of stibonium ylides with carbonyl compounds
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Pentacoordinate 1,2-oxastibetanes 14a-d, which are formal [2 + 2]-cycloadducts of the reactions of stibonium ylides with carbonyl compounds, were successfully synthesized by the reactions of the corresponding bromo-2-hydroxyalkylstiboraiies with NaH. The
- Uchiyama, Yosuke,Kano, Naokazu,Kawashima, Takayuki
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p. 659 - 670
(2007/10/03)
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- A sequential highly stereoselective hydroboration and Suzuki-Miyaura cross-coupling reaction of fluoroalkylated internal acetylenes: A practical one-pot synthesis of fluoroalkylated trisubstituted alkenes
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The one-pot synthesis of trisubstituted alkenes starting from fluoroalkylated internal alkynes was investigated. Hydroboration of the alkynes proceeded in a highly regio- and stereoselective manner to give the corresponding vinylboranes in excellent yields. Without isolation, treatment of the vinylboranes with various aryl halides under the Suzuki-Miyaura cross-coupling conditions gave the fluoroalkylated trisubstituted alkenes in high yields with complete retention of the olefinic geometry.
- Konno, Tsutomu,Chae, Jungha,Tanaka, Tomoo,Ishihara, Takashi,Yamanaka, Hiroki
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p. 690 - 691
(2007/10/03)
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- A facile stereocontrolled approach to CF3-substituted triarylethenes: Synthesis of panomifene
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The stereoselective preparation and Pd-catalyzed cross-coupling reaction of boronates 2 provides a new general and convenient route to CF 3-substituted triaryl ethenes 3, in which the CF3 and Ar3 groups are cis to each other. The synthetic potential was demonstrated by the total synthesis of panomifene (Ar1 = Ar 3 = Ph, Ar2 = 4-(OHCH2CH2NHCH 2CH2O)-C6H4). Bpin = (pinacolato)boryl.
- Liu, Xinyu,Shimizu, Masaki,Hiyama, Tamejiro
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p. 879 - 882
(2007/10/03)
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- Z-trifluoromethyl thioenol ethers, enol ethers, and enamines; reactivity towards organolithium reagents
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Trifluoromethyl enol ethers and thioenol ethers conjugated with an unsaturation in the β-position undergo addition/elimination reactions with organolithium reagents to yield the corresponding trifluoromethyl alkenes while preserving the geometry of the do
- Begue, Jean-Pierre,Bonnet-Delpon, Daniele,Rock, Michael H.
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p. 171 - 174
(2007/10/02)
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- Synthesis of hindered and functionalized 1-CF3 substituted olefins via a carbolithiation-elimination-metalation cascade
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Addition of organolithium reagents to trifluoromethyl enol ethers 1a-d and thio enol ethers 2a provided stereoselectively the corresponding trisubstituted fluoroalkenes 3a-d in 70-90% yields. The products could themselves react with organolithium reagents and undergo a vinyl metalation providing, after trapping with an electrophile, tetrasubstituted olefins in excellent yields and with stereoselectivity. This method can be applied to other fluoroalkyl enol ethers (Rf = C2F5). The product, tetrasubstituted olefin, can be obtained directly from enol ether with 2 equiv of reagent through a carbolithiation-elimination-metalation cascade.
- Bégué, Jean-Pierre,Bonnet-Delpon, Danièle,Bouvet, Denis,Rock, Michael H.
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p. 9111 - 9114
(2007/10/03)
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- REACTIONS EN MILIEU HETEROGENE SOLIDE-LIQUIDE FAIBLEMENT HYDRATE: II - LA REACTION DE WITTIG DANS LES SYSTEMES CARBONATES ALCALINS/SOLVANT ORGANIQUE APROTIQUE
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The use of alkaline carbonates in a slighty hydrated solid-liquid aprotic organic media allowed the synthesis of alkenes from polyfunctionnal aldehydes or activated ketones with high yield in a Z preferential stereochemistry.The reaction mechanism proposed takes in account the specific use of water on the solvation of cationic species at the solid-liquid interface to explain the Z.E alkene ratio.
- Bigot, Yves Le,Delmas, Michel,Gaset, Antoine
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p. 339 - 350
(2007/10/02)
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- Synthesis and X-Ray Structure of (E)-α-(Trifluoromethyl)stilbene
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Starting from benzyltriphenylphosphonium chloride and ω,ω,ω-trifluoroacetophenone α-(trifluoromethyl)stilbene was prepared with 91percent yield with a phase transfer-catalyzed Wittig reaction with solid KF but without bases.The isolated isomer was found b
- Ruban, Gerhard,Zobel, Dieter,Kossmehl, Gerhard,Nuck, Rolf
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p. 3384 - 3388
(2007/10/02)
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- DETERMINATION OF THE CONFIGURATION OF DIASTEREOMERIC ETHANE DERIVATIVES BY 1 H NMR AND 13 C NMR SPECTROSCOPY
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The diastereomers of substituted ethane derivatives were synthesized and their configuration determined by 1 H NMR and 13 C NMR spectroscopy.
- Sohar, P.,Schneider, G.,Abraham, G.,Horvath, T.
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p. 201 - 208
(2007/10/02)
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