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Gavin Chit Tsui - One of the best experts on this subject based on the ideXlab platform.
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Trifluoromethylation of α-diazoesters and α-diazoketones with Fluoroform-derived CuCF3: synergistic effects of co-solvent and pyridine as a promoter
Organic Chemistry Frontiers, 2019Co-Authors: Gavin Chit TsuiAbstract:We herein describe a new protocol for copper-mediated trifluoromethylation of α-diazoesters and α-diazoketones, both using readily available Fluoroform-derived CuCF3. The synergistic effect of using 1,4-dioxane as a co-solvent and pyridine as a promoter is revealed. Reaction conditions are mild and easy to handle, allowing the synthesis of a range of α-trifluoromethyl esters and ketones in one-step from α-diazo carbonyl compounds. The ultimate CF3 source is the inexpensive, nontoxic, industrial waste Fluoroform.
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domino cyclization trifluoromethylation of 2 alkynylanilines using Fluoroform derived cucf3 synthesis of 3 trifluoromethyl indoles
Organic chemistry frontiers, 2018Co-Authors: Kelvin Pak Shing Cheung, Gavin Chit TsuiAbstract:By employing easily accessible 2-alkynylanilines and the well-established Fluoroform-derived CuCF3 reagent, a novel class of 3-(trifluoromethyl)indoles can be synthesized in good yields with no ambiguity of the CF3 position. The method utilizes a domino cyclization/trifluoromethylation strategy to construct the indole cores with the concomitant installation of the CF3 group. The ultimate source of CF3 is the low-cost industrial by-product Fluoroform (CF3H).
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Domino cyclization/trifluoromethylation of 2-alkynylanilines using Fluoroform-derived CuCF3: synthesis of 3-(trifluoromethyl)indoles
Organic Chemistry Frontiers, 2018Co-Authors: Kelvin Pak Shing Cheung, Gavin Chit TsuiAbstract:By employing easily accessible 2-alkynylanilines and the well-established Fluoroform-derived CuCF3 reagent, a novel class of 3-(trifluoromethyl)indoles can be synthesized in good yields with no ambiguity of the CF3 position. The method utilizes a domino cyclization/trifluoromethylation strategy to construct the indole cores with the concomitant installation of the CF3 group. The ultimate source of CF3 is the low-cost industrial by-product Fluoroform (CF3H).
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Synthesis of 2‑(Trifluoromethyl)indoles via Domino Trifluoromethylation/Cyclization of 2‑Alkynylanilines
2018Co-Authors: Kelvin Pak Shing Cheung, Gavin Chit TsuiAbstract:A new method for the synthesis of 2-(trifluoromethyl)indoles using easily accessible 2-alkynylanilines and a well-established Fluoroform-derived CuCF3 reagent is described. This method utilizes a domino trifluoromethylation/cyclization strategy to construct the indole cores with no ambiguity of the CF3 position. The intriguing 3-formyl-2-(trifluoromethyl)indoles can also be synthesized by this protocol, which are useful intermediates for the preparation of trifluoromethylated drug analogues. The ultimate CF3 source is the inexpensive industrial byproduct Fluoroform
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Copper-Mediated Trifluoromethylation–Allylation of Arynes
2018Co-Authors: Xinkan Yang, Gavin Chit TsuiAbstract:An unprecedented three-component copper-mediated vicinal trifluoromethylation–allylation of arynes is described. A wide range of structurally diverse trifluoromethylated allylarenes can be quickly assembled in one step. The application of the method has been demonstrated in the expedient synthesis of the CF3-containing analogue of the antispasmodic drug papaverine. The new reactivity of the [CuCF3] reagent, which is generated from the inexpensive industrial byproduct Fluoroform, is revealed with unique advantages
James P. Reilly - One of the best experts on this subject based on the ideXlab platform.
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the vibrational overtone spectrum of Fluoroform in the δν 4 ch stretching region
Chemical Physics Letters, 1994Co-Authors: Kirk Boraas, James P. ReillyAbstract:Abstract The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region was recorded by intracavity photoacoustic spectroscopy at room temperature and at 166 K with a resolution limited by Doppler broadening. Of the three bands observed, only one shows clearly resolved J rotational structure.
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The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region
Chemical Physics Letters, 1994Co-Authors: Kirk Boraas, James P. ReillyAbstract:Abstract The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region was recorded by intracavity photoacoustic spectroscopy at room temperature and at 166 K with a resolution limited by Doppler broadening. Of the three bands observed, only one shows clearly resolved J rotational structure.
Koichi Mikami - One of the best experts on this subject based on the ideXlab platform.
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Stable (sila)difluoromethylboranes via C-F activation of Fluoroform derivatives.
Chemical communications (Cambridge England), 2017Co-Authors: Shigekazu Ito, Naoto Kato, Koichi MikamiAbstract:Lithium 1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaborol-2-uide activates the C–F linkage of Fluoroform (CF3H) and the Ruppert–Prakash reagent (CF3SiMe3) to provide difluoromethyl-substituted boranes as air-stable compounds.
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computational sn2 type mechanism for the difluoromethylation of lithium enolate with Fluoroform through bimetallic c f bond dual activation
Chemistry: A European Journal, 2016Co-Authors: Kazuya Honda, Travis V. Harris, Miho Hatanaka, Keiji Morokuma, Koichi MikamiAbstract:The reaction mechanism for difluoromethylation of lithium enolates with Fluoroform was analyzed computationally (DFT calculations with the artificial force induced reaction (AFIR) method and solvation model based on density (SMD) solvation model (THF)), showing an SN 2-type carbon-carbon bond formation; the "bimetallic" lithium enolate and lithium trifluoromethyl carbenoid exert the C-F bond "dual" activation, in contrast to the monometallic butterfly-shaped carbenoid in the Simmons-Smith reaction. Lithium enolates, generated by the reaction of 2 equiv. of lithium hexamethyldisilazide (rather than 1 or 3 equiv.) with the cheap difluoromethylating species Fluoroform, are the most useful alkali metal intermediates for the synthesis of pharmaceutically important α-difluoromethylated carbonyl products.
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Computational SN2‐Type Mechanism for the Difluoromethylation of Lithium Enolate with Fluoroform through Bimetallic C−F Bond Dual Activation
Chemistry (Weinheim an der Bergstrasse Germany), 2016Co-Authors: Kazuya Honda, Travis V. Harris, Miho Hatanaka, Keiji Morokuma, Koichi MikamiAbstract:The reaction mechanism for difluoromethylation of lithium enolates with Fluoroform was analyzed computationally (DFT calculations with the artificial force induced reaction (AFIR) method and solvation model based on density (SMD) solvation model (THF)), showing an SN 2-type carbon-carbon bond formation; the "bimetallic" lithium enolate and lithium trifluoromethyl carbenoid exert the C-F bond "dual" activation, in contrast to the monometallic butterfly-shaped carbenoid in the Simmons-Smith reaction. Lithium enolates, generated by the reaction of 2 equiv. of lithium hexamethyldisilazide (rather than 1 or 3 equiv.) with the cheap difluoromethylating species Fluoroform, are the most useful alkali metal intermediates for the synthesis of pharmaceutically important α-difluoromethylated carbonyl products.
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organocatalysis approach to trifluoromethylation with Fluoroform
ChemInform, 2014Co-Authors: Yuan Zhang, Motohiro Fujiu, Hiroki Serizawa, Koichi MikamiAbstract:A new method for the trifluoromethylation of aldehydes, ketones, carboxylic chlorides, and carboxylic esters in the presence of PTBU is described.
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Organocatalysis approach to trifluoromethylation with Fluoroform
Journal of Fluorine Chemistry, 2013Co-Authors: Yuan Zhang, Motohiro Fujiu, Hiroki Serizawa, Koichi MikamiAbstract:Abstract The organic base methodology exploits an access to generate the “trifluoromethyl anion” for carbonyl, ester, acid halide, epoxide, deuterium donor, and carbon dioxide substrates to afford the trifluoromethylation products with good overall efficiency even in organocatalysis conditions. The NMR analysis of the mixture of Fluoroform and P4-base shows no change thereof. However, on addition of electrophiles, the trifluoromethylation products were obtained efficiently.
Kirk Boraas - One of the best experts on this subject based on the ideXlab platform.
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the vibrational overtone spectrum of Fluoroform in the δν 4 ch stretching region
Chemical Physics Letters, 1994Co-Authors: Kirk Boraas, James P. ReillyAbstract:Abstract The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region was recorded by intracavity photoacoustic spectroscopy at room temperature and at 166 K with a resolution limited by Doppler broadening. Of the three bands observed, only one shows clearly resolved J rotational structure.
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The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region
Chemical Physics Letters, 1994Co-Authors: Kirk Boraas, James P. ReillyAbstract:Abstract The vibrational overtone spectrum of Fluoroform in the Δν=4 CH stretching region was recorded by intracavity photoacoustic spectroscopy at room temperature and at 166 K with a resolution limited by Doppler broadening. Of the three bands observed, only one shows clearly resolved J rotational structure.
Benjamin J. Van Der Veken - One of the best experts on this subject based on the ideXlab platform.
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A cryosolution infrared study of the complexes of Fluoroform with ammonia and pyridine: Evidence for a C-H...N pseudo blue-shifting hydrogen bond.
The journal of physical chemistry. A, 2005Co-Authors: Wouter A. Herrebout, Sonia M. Melikova, Konstantin S. Rutkowski, Sofie N. Delanoye, Dimitri N. Shchepkin, Benjamin J. Van Der VekenAbstract:Mid-infrared spectra of mixed solutions in liquid xenon containing Fluoroform and either ammonia or pyridine have been investigated at temperatures between 173 and 213 K. For both Lewis bases, a ne...
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Raman spectroscopy of cryosolutions: the van der Waals complex of dimethyl ether with Fluoroform
Physical Chemistry Chemical Physics, 2004Co-Authors: Tom Van Den Kerkhof, August Bouwen, Etienne Goovaerts, Wouter A. Herrebout, Benjamin J. Van Der VekenAbstract:Raman spectra in the 3200–350 cm−1 range were obtained for solutions in liquid krypton, at 131 K, containing dimethyl ether, Fluoroform and mixtures of them. In the spectra of the mixed solutions bands were detected that must be assigned to the 1∶1 complex between the ether and Fluoroform. The Fluoroform C–H stretching in the complex is detected at 18.7 cm−1 above its value in monomer Fluoroform, confirming the blue shifting hydrogen bonding in the complex. Analysis shows that the Raman intensity of this mode is not significantly affected by complexation. The advantage of the complementarity of the IR and Raman spectra of cryosolutions is demonstrated by the detailed analysis of the methyl deformation modes of the ether.