- Synthesis method for 4,4,4-trifluoro-crotonates
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The invention relates to a synthesis method for 4,4,4-trifluoro-crotonates. The problems that in the prior art, the conversion rate of 3,3,3-trifluoro-allylene is low, and the selectivity of 4,4,4-trifluoro-crotonates is low are mainly solved. The preparing method for the 4,4,4-trifluoro-crotonates includes the step that the 3,3,3-trifluoro-allylene, materials of carbon monoxide and alcohol and acatalyst composition are subjected to a contact reaction to obtain the 4,4,4-trifluoro-crotonates, wherein the catalyst composition comprises a rhodium complex and a high-valence-metal-cation-ocene diphosphonic compound in the technical scheme; the technical problems are well solved, and the synthesis method can be used for industrial production of the 4,4,4-trifluoro-crotonates.
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Paragraph 0037; 0040; 0041; 0042; 0044; 0049; 0054; 0060
(2019/01/16)
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- Stereospecific photochemistry of Δ2-1,2,3-triazolines in solution and in the solid state: Scope and mechanistic studies
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The stereospecific photochemistry of ten N-aryl-substituted cis- or trans-Δ2-1,2,3-triazolines to form the corresponding cis- or trans-aziridines was investigated both in solution and in the solid-state. We found that photochemical reactions in the solid state are more stereospecific than in solution for the 8 crystalline Δ2-1,2,3-triazolines. Additionally, triplet sensitization for some triazolines results in triplet biradicals, which provide the more thermodynamically favored trans-aziridine regardless of the starting triazoline stereochemistry. Product analyses as a function of temperature and solvent polarity suggest that the electronic excitation of the Δ2-1,2,3-triazolines results in the formation of a 1,3-biradical intermediate.
- Chung, Tim S.,Xue, Yang,Carranza, Alberto,Garcia-Garibay, Miguel A.
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p. 1458 - 1463
(2017/09/23)
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- METHOD FOR PREPARATION OF FLUORO, CHLORO AND FLUOROCHLORO ALKYLATED COMPOUNDS BY HOMOGENEOUS CATALYSIS
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The invention discloses a method for preparation of fluoro, chloro and fluorochloro alkylated compounds by homogeneous Pd catalyzed fluoro, chloro and fluorochloro alkylation with fluoro, chloro and fluorochloroalkyl halides in the presence of di(1-adamantyl)-n-butylphosphine and in the presence of 2,2,6,6-tetramethylpiperidine 1-oxyl.
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Page/Page column 21; 22
(2016/06/01)
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- Stereospecific Synthesis of Substituted Aziridines by a Crystal-to-Crystal Photodenitrogenation of δ2-1,2,3-Triazolines
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Crystalline cis- or trans-δ2-1,2,3-triazolines prepared by highly stereospecific and regioselective hydrogen bonding-catalyzed dipolar cycloaddition of activated cis- or trans-alkenes with aryl azides undergo a highly stereospecific photodenitrogenation to form the corresponding cis- or trans- azidirines in high chemical yields. While examples involving disubstituted and trisubstituted triazolines highlight steric challenges encountered in the dipolar cycloaddition reaction, the stereochemical control exerted by the crystalline lattice is enhanced by bulky substituents in the triazoline precursors to generate aziridines photochemically.
- Chung, Tim S.,Lopez, Steven A.,Houk,Garcia-Garibay, Miguel A.
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supporting information
p. 4568 - 4571
(2015/09/28)
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- METABOTROPIC GLUTAMATE RECEPTOR 5 MODULATORS AND METHODS OF USE THEREOF
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Compounds that modulate GluR5 activity and methods of using the same are disclosed.
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Page/Page column 90
(2013/02/27)
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- NMR at earth's magnetic field using para-hydrogen induced polarization
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A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (~1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.
- Hamans, Bob C.,Heerschap, Arend,Andreychenko, Anna,Wijmenga, Sybren S.,Tessari, Marco
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p. 224 - 228,5
(2020/07/30)
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- The effect of fluoromethyl groups on the diastereoselectivity in the electrophilic alkylation
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The effect of fluoromethyl groups on the diastereoselectivity in the electrophilic alkylation is described. In particular, the electrophilic alkylation of enolates with a trifluoromethyl group was proceeded with highly diastereofacial selectivity based on the steric and/or electrostatic effect of substituent with strong electron withdrawing.
- Tamura, Kenji,Yamazaki, Takashi,Kitazume, Tomoya,Kubota, Toshio
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p. 918 - 930
(2007/10/03)
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- Stereospecific Synthesis of Racemic cis- and trans-6-Trifluoromethylshikimic Acids
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Two 'unnatural' derivatives of shikimic acids, cis- and trans-6-trifluoromethylshikimic acid, have been synthesized in their racemic forms via the base-promoted opening of furan Diels-Alder adducts bearing a CF3 group.The relative stereochemistry of the trans-diastereoisomer has been confirmed by an X-ray analysis of its t-butyl ester.
- Leroy, Jacques,Fischer, Nathalie,Wakselman, Claude
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p. 1281 - 1287
(2007/10/02)
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- Regioselectivity in the Ring Opening of 2-Alkylcyclopropylmethyl Radicals: the Effect of Electronegative Substituents
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The regioselectivity of the ring-opening of the trans-2-alkylcyclopropylmethyl radical A to give the primary alkyl radicals B, or the secondary alkyl radicals C, has been investigated, where the groups R and/or CXY carry electronegative substituents.All these reactions gave principally the secondary alkyl radicals C, whereas, in the absence of electronegative substituents, ring-opening occurs in favour of the primary alkyl radicals B.This regioselectivity is interpreted in terms of the frontier orbital interactions which are involved.
- Ratier, Max,Pereyre, Michel,Davies, Alwyn G.,Sutcliffe, Roger
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p. 1907 - 1916
(2007/10/02)
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- PREPARATION OF TRIFLUOROMETHYLATED ALLYLIC ALCOHOLS FROM TRIFLUOROACETALDEHYDE AND ORGANOMETALLIC COMPOUNDS
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A number of allylic alcohols bearing a trifluoromethyl group at the α- or γ-position, and α-trifluoromethylated γ-enols and -ynols were prepared by the reaction of trifluoroacetaldehyde with a variety of organometallic compounds.Most of the Reformatsky- or Grignard-type reactions required promotion by ultrasonic irradiation.
- Ishikawa, Nobuo,Koh, Moon Gyu,Kitazume, Tomoya,Choi, Sam Kwon
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p. 419 - 430
(2007/10/02)
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