- Efficient Asymmetric Biomimetic Aldol Reaction of Glycinates and Trifluoromethyl Ketones by Carbonyl Catalysis
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The direct asymmetric aldol reaction of glycinates represents an intriguing and straightforward strategy to make biologically significant chiral β-hydroxy-α-amino-acid derivatives. But it is not easy to realize the transformation due to the disruption of the reactive NH2 group of glycinates. Inspired by the enzymatic aldol reaction of glycine, we successfully developed an asymmetric aldol reaction of glycinate 5 and trifluoromethyl ketones 4 with 0.1–0.0033 mol % of chiral N-methyl pyridoxal 7 a as the catalyst, producing chiral β-trifluoromethyl-β-hydroxy-α-amino-acid esters 6 in 55–82 % yields (for the syn-diastereomers) with up to >20:1 dr and 99 % ee under very mild conditions. The reaction proceeds via a catalytic cycle similar to the enzymatic aldol reaction of glycine. Pyridoxal catalyst 7 a activates both reactants at the same time and brings them together in a specific spatial orientation, accounting for the high efficiency as well as excellent diastereo- and enantioselectivities.
- Cao, Jing,Cheng, Aolin,Liu, Tao,Song, Guanshui,Zhang, Kun,Zhang, Liangliang,Zhao, Baoguo,Zhao, Guoqing,Zhou, Qinghai
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supporting information
p. 20166 - 20172
(2021/07/20)
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- ASPARAGINE DERIVATIVES AND METHODS OF USE THEREOF
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The present invention relates to compounds of formulas (A) and (I), pharmaceutically acceptable salts thereof, and solvates of any of them, pharmaceutical compositions comprising them, methods of preparation thereof, intermediate compounds useful for the preparation thereof, and methods of treatment or prophylaxis of diseases, in particular cancer, such as colorectal cancer, using these. (A) (I)
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- A Weinreb amide approach to the synthesis of trifluoromethylketones
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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.
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p. 9610 - 9612
(2012/10/29)
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- Trifluoromethyl ketone inhibitors of fatty acid amide hydrolase: A probe of structural and conformational features contributing to inhibition
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The examination of a series of trifluoromethyl ketone inhibitors of Fatty Acid Amide Hydrolase (FAAH, oleamide hydrolase, anandamide amidohydrolase) is detailed in efforts that define structural and conformational properties that contribute to enzyme inhibition and substrate binding. The results imply an extended bound conformation, highlight a role for the presence, position, and stereochemistry of a Δ cis double bond, and suggest little apparent role for C11-C18/C22 of the fatty acid amide substrates.
- Boger, Dale L.,Sato, Haruhiko,Lerner, Aaron E.,Austin, Bryce J.,Patterson, Jean E.,Patricelli, Matthew P.,Cravatt, Benjamin F.
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p. 265 - 270
(2007/10/03)
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- Study for the determination of the absolute configuration of fluoromethylated secondary alcohols by the modified Mosher method
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Application of the modified Mosher method using high-field FT 1H NMR to the 2-methoxy-2-phenyl-2-trifluoromethyl acetic acid (MTPA) derivatives of fluorinated secondary alcohols indicates that this method may be generally used to determine the absolute configurations of these materials.
- Xiao, Ling,Yamazaki, Takashi,Kitazume, Tomoya,Yonezawa, Tetsuo,Sakamoto, Yoshitake,Nogawa, Kouji
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- Efficient synthesis of optically pure 1,1,1-trifluoro-2-alkanols through lipase-catalyzed acylation in organic media
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Lipase-catalyzed esterification was successfully utilized for the optical resolution of 1,1,1-trifluoro-2-alkanol 1 when racemic 1 was treated with lipase from Candida antarctica in hexane in the presence of molecular sieves (4 A) to provide the corresponding (S)-acetate 2 in an optically pure state. Alkanol 1 is known as an important component of liquid crystal compounds which display remarkable ferroelectric liquid crystal (FLC) characteristics. Five types of optically pure alkanols, i.e., 1,1,1-trifluoro-2-octanol (1a), 1,1,1-trifluoro-2-nonanol (1b), 1,1,1-trifluoro-2-decanol (1c), 1,1,1-trifluoro-2-undecanol (1d), and 1,1,1-trifluoro-8-(benzyloxy)-2-octanol (1e), were thus obtained by the lipase-catalyzed acylation.
- Hamada, Hiroki,Shiromoto, Mizuho,Funahashi, Makoto,Itoh, Toshiyuki,Nakamura, Kaoru
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p. 2332 - 2336
(2007/10/03)
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- Halogenation of 1-trifluoromethyl enamines: A new and efficient synthesis of α-bromo-and α-iodo-trifluoromethyl ketones
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Treatment of the 1-trifluoromethyl enamines 1a-d with bromine or iodine results in the formation of the corresponding iminium salts. Treatment of any of these salts with methanol results in the formation of the corresponding α-halo-trifluoromethyl ketones
- Begue, Jean-Pierre,Bonnet-Delpon, Daniele,Bouvet, Denis,Rock, Michael H.
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- Chiral Synthesis Via Organoboranes. 38 Selective Reductions. 48. Asymmetric Reduction of Trifluoromethyl Ketones by B-Chlorodiisopinocampheylborane in High Enantiomeric Purity
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(-)-B-Chlorodiisopinocampheylborane TM,1>, introduced by us several years ago, has been shown to reduce prochiral aryl and alkyl perfluorinated ketones to the corresponding optically active alcohols in very high ee.For example, 2,2,2-trifluoroacetophenone, trifluoroacetyl-1-naphthalene, and trifluoroacetyl-2-naphthalene are all reduced with 1 within 1-3 d at rt in 90percent ee, 78percent ee and 91percent ee, respectively.The optical purity of 1-phenyl-2,2,2-trifluoroethanol is upgraded to = 99percent ee by crystallizing the initially formed products from pentane. 1,1,2,2,2- pentafluoropropiophenone and 1,1,2,2,3,3,3-heptafluorobutyrophenone are reduced in 3 d with 1 to the corresponding alcohols in 92percent ee and 87 percent ee, respectively.The reagent reduces alkyl trifluoromethyl ketones at a rate faster than that of the aryl derivatives, while still providing the product alcohols in very high ee.Thus, 1,1,1-trifluoroacetone, 1,1,1-trifluorononan-2-one, and 1,1,1-trifluorodecan-2-one are all reduced within 4 - 8 h in 89percent ee, 92percent ee, and 91percent ee, respectively.Even α-sec-alkyl trifluoromethyl ketones are handled by 1 very efficiently.Thus cyclohexyl trifluoromethyl ketone is reduced by 1 at rt in 12 h to the product alcohol in 87percent ee.In all of these cases the trifluoromethyl group acts as the enantiocontrolling larger group as compared to the aryl or alkyl group.This produces alcohol products with stereochemistry opposite to those obtained for the corresponding hydrogen analogs.The steric and electronic influence of the trifluoromethyl group in achieving enantiocontrol in assymmetric reductions is discussed.Keywords: asymmetric reduction; trifluoromethyl ketones; DIP-Chloride; high enantiomeric purity
- Ramachandran, P. Veeraraghavan,Teodorovic, Aleksandar V.,Brown, Herbert C.
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p. 1725 - 1738
(2007/10/02)
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- The Wittig Reaction of Perfluoro Acid Derivatives: Access to Fluorinated Enol Ethers, Enamines, and Ketones
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The preparation of novel perfluoroalkyl-substituted compounds in good yields is described.This preparation involves the Wittig reaction of a phosphonium ylide with perfluoroalkyl acid derivatives.The influence of the structure of the starting alkylidenetr
- Begue, Jean-Pierre,Bonnet-Delpon, Daniele,Mesureur, Dany,Nee, Gerard,Wu, Sheng-Wen
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p. 3807 - 3814
(2007/10/02)
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- NOUVELLE SYNTHESE DE TRIFLUOROMETHYLCETONES ET D' α-BROMO TRIFLUOROMETHYLCETONES
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We report a new method for the preparation of trifluoromethylketones, as an alternative to the use of organometallics.The condensation of phosphonium ylides with trimethylsilyl trifluoroacetate provides silyloxy enol ethers whose hydrolysis leads to trifluoromethylketones.Bromation of the same silyloxy enol ether is also a convenient preparation of α-bromo trifluoromethylketone.
- Begue, J. P.,Mesureur, D.
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p. 271 - 282
(2007/10/02)
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