- (Z) -Trifluoromethyl-Trisubstituted Alkenes or Isoxazolines: Divergent Pathways from the Same Allene
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Because of a charge-dipole interaction involving nonbonding electron pairs on fluorine, protonation of trifluoromethyl allenes leads to tri- or tetrasubstituted alkenes with high (Z)-selectivity. Treatment of the same allenes with catalytic Au(I) initiates a reaction cascade that produces isoxazolines in high yield.
- Liu, Chaolun,Rowland, Casey A.,Tius, Marcus A.,Yap, Glenn P. A.
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supporting information
p. 7208 - 7212
(2020/10/02)
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- Catalytic asymmetric hydrogenation of α-CF3- or β-CF3-Substituted acrylic acids using Rhodium(I) complexes with a combination of chiral and achiral ligands
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Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or β position were efficiently hydrogenated in the presence of a RhI complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99 %) and high enantioselectivity (92->99 %). Copyright
- Dong, Kaiwu,Li, Yang,Wang, Zheng,Ding, Kuiling
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supporting information
p. 14191 - 14195
(2014/01/06)
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- Catalytic aerobic oxidative decarboxylation of α-trifluoromethyl-α-hydroxy acids to trifluoromethyl ketones
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The oxidative decarboxylation of α-trifluoromethyl-α-hydroxy acids to trifluoromethyl ketones is carried out under mild catalytic aerobic conditions using a cobalt(III) complex in the presence of pivalaldehyde.
- Blay, Gonzalo,Fernández, Isabel,Marco-Aleixandre, Alicia,Monje, Belén,Pedro, José R,Ruiz, Rafael
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p. 8565 - 8571
(2007/10/03)
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- New catalytic oxidation of trifluoromethyl carbinols by a ruthenium(II) complex
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The first catalytic oxidation of trifluoromethyl carbinols has been accomplished by a novel ruthenium(II) complex using sodium periodate as an oxidant. Trifluoromethyl ketones were obtained under mild conditions and in excellent yields. (C) 2000 Elsevier Science Ltd.
- Kesavan, Venkitasamy,Bonnet-Delpon, Danièle,Bégué, Jean-Pierre,Srikanth, Abirami,Chandrasekaran, Srinivasan
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p. 3327 - 3330
(2007/10/03)
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- Direct preparation of trifluoromethyl ketones from carboxylic esters: Trifluoromethylation with (trifluoromethyl)trimethylsilane
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Previously difficult to prepare, alipathic and alicyclic trifluoromethylketones (e.g. 1 and 2), which are of pharmacologic interest as potential enzyme inhibitors, can now be synthesized easily and efficiently. The one-step reaction starting with carbonic esters and trimethyl(trifluoromethyl)silane is induced by tetrabutylammonium fluoride in nonpolar, aprotic solvents and proceeds without formation of double-addition products.
- Wiedemann, Juergen,Heiner, Thomas,Mloston, Gregorz,Prakash, G.K. Surya,Olah, George A.
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p. 820 - 821
(2007/10/03)
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- Process for preparing trifluoromethyl ketones
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A process is described for preparing trifluoromethyl ketones of the formula I STR1 where R has the given meanings, wherein an alcohol of the formula II STR2 is reacted with a compound of the formula IV where n has the given meaning.
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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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- Reactions of trifluoromethyl ketones. VIII. Investigation of steric effects of a trifluoromethyl group through ene reaction of trifluoromethyl ketones
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In the course of our study on the ene reaction of trifluoromethyl ketones, a trifluoromethyl group has been observed to behave as a larger substituent than commonly believed in the biomedicinal field. To estimate the steric eflect of a trifluoromethyl gro
- Nagai,Nishioka,Koyama,Ando,Miki,Kumadaki
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p. 593 - 598
(2007/10/02)
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- A novel access to 4-fluoropyrimidines from α-chloro-α'-trifluoromethylketones
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When treated with formamidine acetate and KOH, α-chloro-α'-trifluoromethyl ketones afford, though in moderate yield, 4-fluoropyrimidine derivatives.
- De Nanteuil
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p. 2467 - 2468
(2007/10/02)
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- Oxidation of Fluoroalkyl-Substituted Carbinols by the Dess-Martin Reagent
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The efficient oxidation of mono-, di-, tri-, and perfluoroalkyl-substituted carbinols has been accommplished by the Dess-Martin periodinane oxidant.A variety of functional groups are compatible with the oxidation procedure.Monitoring the oxidation by 19F NMR indicated that a discreet periodinane intermediate is formed during the course of the reaction.Nonnucleophilic or sterically encumbered α-thiofluoro carbinols were readily oxidized; however, a nucleophilic α-thio-substituted trifluoromethyl carbinol was not.A tert-butyl alcohol modified periodinane oxidant was ultimately employed to achieve oxidation in this example.
- Linderman, Russell J.,Graves, David M.
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p. 661 - 668
(2007/10/02)
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- AN EFFICIENT PROCEDURE FOR THE OXIDATION OF FLUORINATED CARBINOLS
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The oxidation of di and trifluorocarbinols has been accomplished in high yields using the Dess-Martin periodane oxidant.
- Linderman, Russell J.,Graves, David M.
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p. 4259 - 4262
(2007/10/02)
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