- Novel synthesis method for 4,4,4-trifluorobutanol
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The invention relates to a novel synthesis method for 4,4,4-trifluorobutanol. The method comprises the following steps: (1) enabling diethyl malonate to be subjected to substitution reaction with 2,2,2-trifluoro ethyl p-toluenesulfonate under the catalysis of a basic catalyst, so as to obtain 2-(2,2,2-trifluoro ethyl)-diethyl malonate; (2) enabling 2-(2,2,2-trifluoro ethyl)-diethyl malonate to be subjected to decarboxylic reaction, so as to obtain 4,4,4-trifluoro ethyl butyrate; and (3) reducing 4,4,4-trifluoro ethyl butyrate by a reduction reagent under the catalysis of a catalyst, thereby obtaining 4,4,4-trifluorobutanol. Compared with the prior art, the method disclosed by the invention has the advantages that the raw materials are cheap and readily-available, the cost is low, the number of synthesis steps is small, the operation is convenient and safe, the aftertreatment is simple, the solvent can be cyclically applied mechanically and is environment-friendly, the reaction yield is high, and the product is high in purity and good in quality and is applicable to industrial application.
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Paragraph 0055; 0056; 0057
(2016/10/08)
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- Pichia stipitis OYE 2.6 variants with improved catalytic efficiencies from site-saturation mutagenesis libraries
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An earlier directed evolution project using alkene reductase OYE 2.6 from Pichia stipitis yielded 13 active site variants with improved properties toward three homologous Baylis-Hillman adducts. Here, we probed the generality of these improvements by testing the wild-type and all 13 variants against a panel of 16 structurally-diverse electron-deficient alkenes. Several substrates were sterically demanding, and as hoped, creating additional active site volume yielded better conversions for these alkenes. The most impressive improvement was found for 2-butylidenecyclohexanone. The wild-type provided less than 20% conversion after 24 h; a triple mutant afforded more than 60% conversion in the same time period. Moreover, even wild-type OYE 2.6 can reduce cyclohexenones with very bulky 4-substituents efficiently.
- Patterson-Orazem, Athéna,Sullivan, Bradford,Stewart, Jon D.
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p. 5628 - 5632
(2015/01/09)
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- Practical asymmetric synthesis of trifluoromethyl-containing aminoester using a modified davis protocol
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Practical synthesis of aminoester 1 starting from 1,1,1-trifluoro-3- iodopropane is presented. Use of Ti(Oi-Pr)4 as a Lewis acid for condensation of intermediate aldehyde 8 with (S)-(+)-p-toluenesulfinamide was found to be critical. Conditions for a reproducible and high-yielding Wittig reaction of aldehyde hydrate with phosphorus ylide 4, that appear to have general applicability, are described.
- Alirnardanov, Asaf,Schmid, Jean,Afragola, Jay,Khafizova, Gulnaz
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p. 424 - 428
(2013/01/03)
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- Convenient synthesis of fluorinated alkanes and cycloalkanes by hydrogenation of perfluoroalkylalkenes under ultrasound irradiation
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Synthesis of several 1,4-disubstituted cyclohexanes, by hydrogenation of sterically hindered and electron poor perfluoroalkyl alkenes, was performed, at room temperature under hydrogen at atmospheric pressure. Hydrogenation was difficult to achieve without ultrasound whatever catalyst and pressure (from 1 to 120 bar) used. Coupling of ultrasonic irradiation with metallic catalysis dramatically increased the efficiency of hydrogenation of perfluoroalkyl alkenes.
- Carcenac,Tordeux,Wakselman,Diter
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p. 1347 - 1355
(2007/10/03)
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- Process for preparing fluorine-containing carboxylic acid ester
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An improved process for preparing a fluorine-containing carboxylic acid ester useful as an intermediate for producing a fluorine-containing carboxylic acid is disclosed. The process comprises reacting a fluorine-containing alkyl halide with carbon monoxide and an alcohol in the presence of a transition metal catalyst of the Group VIII of the Periodic Table and a base, and provides the desired carbonylated compound in high yield.
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- CARBONYLATION OF 1-PERFLUOROALKYL-SUBSTITUTED 2-IODOALKANES CATALYZED BY TRANSITION-METAL COMPLEXES
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Carboxylic acids and esters with perfluoroalkyl substituent at β position were synthesized in good yields from 1-perfluoroalkyl-substituted 2-iodoalkanes and carbon monoxide with water or alcohols in the presence of base by using group VIII transition-metal complexes as catalysts.
- Urata, Hisao,Kosukegawa, Osamu,Ishii, Yoshimitsu,Yugary, Hideki,Fuchikami, Takamasa
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p. 4403 - 4406
(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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- Regioselective Hydroesterification and Hydrocarboxylation of 3,3,3-Trifluoropropene and Pentafluorostyrene Catalyzed by Phosphine-Palladium Complex
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The hydroesterification and hydrocarboxylation of 3,3,3-trifluoropropene (TFP) and pentafluorostyrene (PFS) catalyzed by phosphine-palladium complexes were studied.It was found that the efficiency and the product distribution of the reaction depended markedly on the nature of nucleophile, i. e., water or alcohol, the structures of olefin and phosphine ligand, and other reaction variables such as solvent, temperature, and carbon monoxide pressure.Under optimal conditions either unbranched products or branched products were obtained in high yields with high regioselectivities.For example, 4,4,4-trifluorobutyric acid (5a) was obtained in 93percent yield with 99percent regioselectivity by using PdCl2(dppf)-SnCl2 as the catalyst in the hydrocarboxylation of TFP while ethyl 2-methyl-3,3,3-trifluoropropionate (2a) was obtained in 96percent yield with 79percent regioselectivity in the hydroesterification of TFP by using PdCl2(PPh3)2 as the catalyst.Similarly, 3-(pentafluorophenyl)propionic acid (5b) was obtained in 93percent yield with 99percent regioselectivity in the hydrocarboxylation of PFS catalyzed by PdCl2(dppf), and methyl 2-(pentafluorophenyl)propionate (2b) was obtained in 89percent yield with 95percent regioselectivity in the hydroesterification of PFS catalyzed by PdCl2(PPh3)2.Possible mechanisms of the present reactions are discussed.The hydrocarboxylations of TFP and PFS may involve (hydroxycarbonyl)palladium(II) intermediates while the hydroesterifications of TFP and PFS may proceed via alkylpalladium(II) and acylpalladium(II) intermediates.
- Fuchikami, Takamasa,Ohishi, Katsuyuki,Ojima, Iwao
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p. 3803 - 3807
(2007/10/02)
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