72487-06-0Relevant articles and documents
Control of enantioselectivity of lipase-catalyzed esterification in supercritical carbon dioxide by tuning the pressure and temperature
Matsuda, Tomoko,Kanamaru, Ryuzo,Watanabe, Kazunori,Kamitanaka, Takashi,Harada, Tadao,Nakamura, Kaoru
, p. 2087 - 2091 (2003)
The enantioselectivity of lipase-catalyzed esterification of 1-(p-chlorophenyl)-2,2,2-trifluoroethanol in supercritical carbon dioxide was controlled by tuning the pressure and temperature. The enantioselectivity was higher at low pressure and low temperature (E=60) than at high pressure and high temperature (E=10). At the density of 0.75 g/mL, a modified Eyring plot of ln E against 1/T was found to be linear, as expected from the theory on the effects of temperature on stereochemistry.
Control on enantioselectivity with pressure for lipase-catalyzed esterification in supercritical carbon dioxide
Matsuda, Tomoko,Kanamaru, Ryuzo,Watanabe, Kazunori,Harada, Tadao,Nakamura, Kaoru
, p. 8319 - 8321 (2001)
The enantioselectivity of lipase-catalyzed esterification of 1-(p-chlorophenyl)-2,2,2-trifluoroethanol in supercritical carbon dioxide changed continuously from E = 10 to 50 by decreasing the pressure at 55°C. The effect of the solvent on enantioselectivi
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
Bao, Robert Li-Yuan,Fu, Kang,Shi, Lei
supporting information, (2021/11/27)
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.
A Hammett Study of Clostridium acetobutylicum Alcohol Dehydrogenase (CaADH): An Enzyme with Remarkable Substrate Promiscuity and Utility for Organic Synthesis
Berkowitz, David B.,Kudalkar, Gaurav P.,Lee, Joshua D.,Tiwari, Virendra K.
supporting information, p. 237 - 247 (2020/02/18)
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.
Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands
Brüning, Fabian,Nagae, Haruki,K?ch, Daniel,Mashima, Kazushi,Togni, Antonio
supporting information, p. 10818 - 10822 (2019/07/31)
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.
Visible light-promoted umpolung coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines
Xu, Xiao,Min, Qing-Qiang,Li, Na,Liu, Feng
supporting information, p. 11017 - 11020 (2018/10/08)
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.
Asymmetric Construction of Pyrrolidines Bearing a Trifluoromethylated Quaternary Stereogenic Center via CuI-Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides with β-CF3-β,β-Disubstituted Nitroalkenes
Tang, Li-Wei,Zhao, Bao-Jing,Dai, Li,Zhang, Man,Zhou, Zhi-Ming
supporting information, p. 2470 - 2477 (2016/09/13)
A direct and convenient method has been developed for the synthesis of optically active pyrrolidines bearing a quaternary stereogenic center containing a CF3 group at the C-3 position of the pyrrolidine ring. The synthesis system, CuI/Si-FOXAP-catalyzed exo-selective 1,3-dipolar cycloaddition of azomethine ylides with β-CF3-β,β-disubstituted nitroalkenes, provides pyrrolidines with high diastereoselectivities (up to >98:2 d.r.) and excellent enantioselectivities (up to >99.9 ee) and performs well for a broad scope of substrates under mild conditions.
A method of manufacturing a trifluoromethyl group-containing compound
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Paragraph 0046; 0050; 0051, (2018/02/10)
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.)
Photoinduced additive-free trifluoromethylation of aromatic aldehydes with TMSCF3
Sun, Jing,Peng, Xinhua,Guo, Hao
supporting information, p. 797 - 800 (2015/01/30)
We report herein a new and effective method for additive-free trifluoromethylation of aromatic aldehydes with TMSCF3. Normal acidic hydrolysis for desilylation in the workup process is not required in this transformation. This reaction presents
Chemo- and Enantioselective Addition and β-Hydrogen Transfer Reduction of Carbonyl Compounds with Diethylzinc Reagent in One Pot Catalyzed by a Single Chiral Organometallic Catalyst
Huang, Huayin,Zong, Hua,Bian, Guangling,Song, Ling
, p. 12614 - 12619 (2016/01/09)
Using a single chiral phosphoramide-Zn(II) complex as the catalyst, the asymmetric β-H transfer reduction of aromatic α-trifluoromethyl ketones and enantioselective addition of aromatic aldehydes with Et2Zn in one pot were successfully realized, affording the corresponding additive products of secondary alcohols in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee) and the reduction products of α-trifluoromethyl alcohols in good to excellent yields with up to 77% ee.
