cas 454-31-9, Ethyl difluoroacetate | Articles data

Articles about 454-31-9Total 36 be found

Article title
Article abstract
Author
Journal number and time
Download

Tandem Difluoroalkylation-Arylation of Enamides Catalyzed by Nickel
A nickel-catalyzed three-component reaction for the synthesis of difluoroalkylated compounds through tandem difluoroalkylation-arylation of enamides has been developed. The reaction tolerates a variety of arylboronic acids and widely available difluoroalkyl bromides, and even the relatively inert substrate chlorodifluoroacetate. The significant advantages of this protocol are the low-cost nickel catalyst, synthetic convenience, excellent functional-group compatibility and high reaction efficiency.
Gu, Ji -Wei,Min, Qiao -Qiao,Yu, Ling -Chao,Zhang, Xingang
p. 12270 - 12274
(2016)
Read Online

Photoluminescence of Seven-Coordinate Zirconium and Hafnium Complexes with 2,2′-Pyridylpyrrolide Ligands
Luminescent seven-coordinated zirconium and hafnium complexes bearing three mono-anionic 2,2′-pyridylpyrrolide ligands and one chloride were synthesized. Solid-state structures and the dynamic behaviors in solution were probed by X-ray crystallography and variable temperature 1H NMR experiments, respectively. Absorption spectroscopy and time-dependent density functional theory (TD-DFT) calculations supported a hybrid of ligand-to-metal charge transfer (LMCT)/ligand-to-ligand charge transfer (LLCT) for the visible light absorption band. The complexes (MePMPMe)3MCl (M=Zr, Hf, MePMPMe=3,5-dimethyl-2-(2-pyridyl)pyrrolide) are emissive in solution at room temperature upon irradiation with visible light due to a combination of phosphorescence and fluorescence characterized by excited state lifetimes in the μs and low to sub-ns timescale, respectively. Electrochemical experiments revealed that the zirconium complex possesses a reversible redox event under highly reducing condition (?2.29 V vs. Fc+/0).
Zhang, Yu,Akhmedov, Novruz G.,Petersen, Jeffrey L.,Milsmann, Carsten
p. 3042 - 3052
(2019)
Read Online

Diethylzinc-Mediated Radical 1,2-Addition of Alkenes and Alkynes
A novel diethylzinc-mediated radical 1,2-addition of perfluoroalkyl iodides to unactivated alkenes and alkynes is presented, which demonstrates a novel way to generate an ethyl difluoroacetate radical. This method is highly efficient and gives full conversions of the substrates, high yields of the products, and negligible byproducts and requires no column chromatography purifications. The mild conditions enable this protocol to exhibit excellent functional group compatibility.
Li, Xin,He, Songtao,Song, Qiuling
supporting information
p. 2994 - 2999
(2021/05/04)

Access to α,α-Difluoro-γ-amino Acids by Nickel-Catalyzed Reductive Aryldifluoroacetylation of N -Vinylacetamide
A nickel-catalyzed reductive aryldifluoroacetylation of N -vinylacetamide with ethyl chloro(difluoro)acetate and aryl iodides is described. This chelating amide carbonyl group-assisted strategy provides rapid access to a variety of protected α,α-difluoro-γ-amino acids that might have potential applications in peptide chemistry and protein engineering. An advantage of this method is its synthetic simplicity, with no preparation of organometallic reagents.
Zhao, Qing-Wei,Yang, Zhi-Fang,Fu, Xia-Ping,Zhang, Xingang
supporting information
p. 1565 - 1569
(2020/11/16)

trans-Selective Aryldifluoroalkylation of Endocyclic Enecarbamates and Enamides by Nickel Catalysis
Efficient methods for the dicarbofuntionalization of the cyclic alkenes 2-pyrroline and 2-azetine are limited. Particularly, the dicarbofunctionalization of endocyclic enecarbamates to achieve fluorinated compounds remains an unsolved issue. Reported here is a nickel-catalyzed trans-selective dicarbofunctionalization of N-Boc-2-pyrroline and N-Boc-2-azetine, a class of endocyclic enecarbamates previously unexplored for transition metal catalyzed dicarbofunctionalization. The reaction can be extended to six- and seven-membered endocyclic enamides. A variety of arylzinc reagents and bromodifluoroacetate, and its derivatives, undergo the reaction, providing straightforward and efficient access to an array of pyrrolidine- and azetidine-containing fluorinated amino acids and oligopeptides, which may have applications in the life sciences.
Cheng, Ran,Luo, Yun-Cheng,Wang, Ming-Kuan,Xu, Chang,Zhang, Xingang
supporting information
p. 18741 - 18747
(2020/08/26)

Method for co-producing 2-fluoropropionate and ethyl difluoroacetate
The invention discloses a method for co-producing 2-fluoropropionate and ethyl difluoroacetate. The method comprises: (a) carrying out a reaction on a fluorinating reagent and a lactate for 0.5-7 h ata reaction temperature of 30-120 DEG C according to a molar ratio of 0.5-2:1, cooling the reaction material after completing the reaction, adding a nitrogen-containing compound, and carrying out pressure reducing rectification to obtain a 2-fluoropropionate product and N,N-dimethyl difluoroacetamide; and (b) adding concentrated sulfuric acid to a mixture of anhydrous ethanol and the N,N-dimethyldifluoroacetamide obtained in the step (a), carrying out a reaction for 1-10 h at a reaction temperature of 50-170 DEG C, cooling after completing the reaction, separating the liquid, and carrying outrectification to obtain the ethyl difluoroacetate product, wherein a molar ratio of anhydrous ethanol to N,N-dimethyl difluoroacetamide is 0.5-4.5:1, and a molar ratio of concentrated sulfuric acid to N,N-dimethyl difluoroacetamide is 0.1-1.5:1. According to the present invention, the method has advantages of environmental protection, high yield and low cost.
-
Paragraph 0035; 0037; 0038; 0040; 0041; 0043; 0044; 0046

(2019/05/04)

Alkene Carboarylation through Catalyst-Free, Visible Light-Mediated Smiles Rearrangement
A light-mediated Truce–Smiles arylative rearrangement is described that proceeds in the absence of any photocatalyst. The protocol creates two C?C bonds from simple starting materials, with the installation of an aryl ring and a difluoroacetate moiety across unactivated alkenes. The reaction proceeds via a radical mechanism, utilizing a light-mediated reduction of ethyl bromodifluoroacetate by N,N,N′,N′-tetramethylethylenediamine (TMEDA) to set up intermolecular addition to an unactivated alkene, followed by Truce–Smiles rearrangement.
Whalley, David M.,Duong, Hung A.,Greaney, Michael F.
p. 1927 - 1930
(2019/01/16)

Method for preparing ethyl bromodifluoroacetate
The invention provides a method for preparing ethyl bromodifluoroacetate and relates to a preparation method of a chemical reagent. The method takes trichloro ethylene as a raw material, and comprisesthe following steps: under the action of ultraviolet light of a catalytic medium, an oxidation reaction happens between trichloro ethylene and oxygen in a reactor to synthesize dichloracetyl chloride; an amination reaction happens between dichloracetyl chloride and diethylamine under the action of a catalyst to synthesize dichloroacetyl diethylamine; a fluorination reaction happens between dichloroacetyl diethylamine and anhydrous potassium fluoride under the action of a solvent and a phase transfer catalyst to synthesize difluoroacetyl diethylacetamide; difluoroacetyl diethylacetamide is esterified to synthesize ethyl difluoroacetate; and by taking cupric bromide as a brominating agent, ethyl difluoroacetate is bromized to prepare the end product (ethyl bromodifluoroacetate). The methodhas the characteristics that the equipment investment is low, reaction conditions are mild, the method is safely implemented at normal pressure, and after-treatment is simple.
-
Paragraph 0027

(2018/04/02)

A 4, 4 - difluoro-acetyl-acetic acid alkyl ester preparation method
The invention discloses a method for preparing alkyl 4,4-difluoroacetylacetate. The method has the advantages of easily available raw materials, simple process flow, safety in operation and high yield. The method comprises the following steps: (1) carrying out hydrolysis reaction on 1,1,2,2-tetrafluoroethyl ether used as a raw material and water in an acid and separating to obtain ethyl difluoroacetate and hydrogen fluoride; (2) reacting ethyl difluoroacetate obtained in the step (1) and alkyl acetate in the presence of an alkaline catalyst to obtain 1,1-difluoro-2-butenoic acid alkyl ester-2-hydroxy salt; and (3) neutralizing 1,1-difluoro-2-butenoic acid alkyl ester-2-hydroxy salt obtained in the step (2) and hydrogen fluoride to obtain alkyl 4,4-difluoroacetylacetate.
-
Paragraph 0054

(2017/08/25)

MANUFACTURING METHOD OF ESTER COMPOUND
PROBLEM TO BE SOLVED: To provide a manufacturing method of an ester compound capable of recovering the ester compound at high purity and being manufactured with simple method at low cost. SOLUTION: There is provided a manufacturing method of an ester compound represented by the general formula (1): RACOORB, where RA and RB is an alkyl group, a halogenated alkyl group, an ether oxygen atom-containing alkyl group or an ether oxygen atom-containing alkyl group substituted by one or more halogen atom, and RA and RB may be same or different. It has a process A for contacting a compound represented by the general formula (2): RACF2ORB, where RA and RB are same as the formula (1), with an acid catalyst in presence of a material containing SiO2 and RBOH, where RB is same as the formula (1), so as to obtain a crude product containing the ester compound and hydrogen fluoride, and a process B for purifying the crude product by adding alkali to the crude product. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
-
Paragraph 0064-0071

(2018/01/06)

Purification of organic compounds (by machine translation)
[Problem] high purity organic compound can be recovered, further, an organic compound can be purified by a purification method for inexpensively by a simple method. The present invention is an organic compound [a] purification method, organic compounds, hydrogen fluoride, SiO2 The process for preparing a material containing a mixture comprising A, adding alkali to the mixture B, is provided. Therefore, high purity organic compound can be recovered, which, by a simple method which can be purified. [Drawing] no (by machine translation)
-
Paragraph 0094; 0098-0099

(2018/01/09)

Synthesis technology of ethyl difluoroacetate
The invention relates to a production technology of ethyl difluoroacetate, specifically to a synthesis technology of ethyl difluoroacetate. The technology comprises the following steps: (1) 2,2,2-trifluoroethyl alcohol and chloroethane are subjected to an etherification reaction under the action of a catalyst so as to obtain trifluoro ethyl ether; (2) trifluoro ethyl ether obtained in the step (1) undergoes a defluorination reaction under the alkaline condition to generate difluoro ethyl vinyl ether; (3) difluoro ethyl vinyl ether obtained in the step (2) and ethanol are subjected to an addition reaction in the presence of a catalyst p-toluenesulfonic acid so as to obtain acetal; and (4) acetal obtained in the step (3) is oxidized under the combined action of hydrogen peroxide and vanadic anhydride so as to obtain ethyl difluoroacetate. The invention has the following beneficial effects: the synthesis method is simple, has characteristics of less pollution, high product purity and low production cost, etc., and provides a new approach to large-scale production of ethyl difluoroacetate.
-
Paragraph 0049

(2017/06/30)

Method for preparing difluoroethanol through catalytic hydrogenation
The invention provides a method for preparing difluoroethanol through catalytic hydrogenation. The method has the beneficial effects that hydrogenation reduction reaction is carried out by using ethyl chlorodifluoroacetate as the raw material, a Pd/C as a catalyst, triethylanmine as an acid-binding agent and ethanol as a solvent; the atom F has higher electronegativity and HF can not be generated in the ethyl chlorodifluoroacetate hydrogenation process, but the C-Cl bond is easy to hydrogenate and HCl is easy to generate, thus neutralizing generated HCl by adding the acid-binding agent triethylanmine, propelling reaction to be carried out positively and increasing the conversion rate of ethyl chlorodifluoroacetate; on the other side, used in ester hydrogenation reaction, the Pd/C catalyst has good characteristics of low hydrogen-ester ratio, high raw material conversion rate, high alcohol selectivity, stable catalyst, and the like; and therefore, the method has the effect of solving the problems that the reaction process in the traditional ester hydrogenation process is complex, is high in investment and is not suitable for small-scale production in the fine chemical industry field.
-
Paragraph 0037-0038

(2017/06/02)

Preparation technique of ethyl difluoroacetate
The invention discloses a preparation technique of ethyl difluoroacetate. The preparation technique comprises the following steps: sequentially adding halogenated ethyl difluoroacetate, triethylamine, a solvent and a catalyst into a high-pressure reaction kettle; replacing air in the reaction kettle with nitrogen, replacing with hydrogen, and heating to perform hydrogenation reaction until the kettle pressure reaches the standard value; when the kettle pressure drops, repeatedly introducing hydrogen until the kettle pressure no longer drops; and finally, carrying out rectification reaction, carrying out normal-pressure rectification operation on the obtained product in a glass bottle to separate out the product ethyl difluoroacetate, and carrying out filtration and water washing on the kettle bottom material to recover the catalyst for the reaction next time. By adopting the halogenated ethyl difluoroacetate as the raw material, the preparation technique of ethyl difluoroacetate has the advantages of simple preparation process, high product purity (at least 99.5%) and high yield (at least 95%), and the catalytic efficiency of the palladium-carbon catalyst does not obviously descend after the palladium-carbon catalyst is recovered 10 times, thereby enhancing the benefits of the enterprise.
-
Paragraph 0025; 0026

(2017/06/10)

Synthesizing method for ethyl difluoroacetate
The invention relates to a synthesizing method, in particular to a synthesizing method for ethyl difluoroacetate, and aims at solving the problems that an existing synthesizing method for the ethyl difluoroacetate is complex in technological process, low in safety and high in preparation cost. The synthesizing method comprises the steps that 1, a catalyst is prepared, wherein a tubular reactor is filled with Al2O3 powder with the certain particle size meshes, it is guaranteed that the height of the Al2O3 powder is in a heating area of the tubular furnace, the temperature is increased to 250 DEG C-300 DEG C under nitrogen protection and kept for 12 h, CHaFbClc gas is continuously and slowly introduced for a reaction, the reaction temperature is set at 250 DEG C-300 DEG C, and the reaction time is set for 12 h; 2, 1,1,2,2-tetrafluoroethyl ethylether is taken as raw materials for a reaction under the conditions of the certain temperature and the catalyst, and an intermediate does not need to be separated and is directly collected through condenser to be converted into ethyl ester. The method belongs to the field of chemical engineering.
-
Paragraph 0032-0042

(2017/03/24)

A Luminescent Zirconium(IV) Complex as a Molecular Photosensitizer for Visible Light Photoredox Catalysis
Titanium and zirconium complexes carrying two 2,6-bis(pyrrolyl)pyridine ligands have been synthesized and characterized. The neutral complexes Ti(MePDP)2 and Zr(MePDP)2 (MePDP = 2,6-bis(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine) show intense ligand-to-metal charge-transfer bands in the visible region and undergo multiple reversible redox events under highly reducing conditions. Zr(MePDP)2 exhibits photoluminescent behavior and its excited state can be quenched by mild reductants to generate a powerful electron transfer reagent with a ground state potential of -2.16 V vs Fc+/0. This reactivity was utilized to facilitate dehalogenation reactions, the reduction of electron-poor olefins, and the reductive coupling of benzyl bromide via photoredox catalysis. In these reactions, the earth-abundant metal complex Zr(MePDP)2 acts as a substitute for the precious metal photosensitizer [Ru(bpy)3]2+.
Zhang, Yu,Petersen, Jeffrey L.,Milsmann, Carsten
p. 13115 - 13118
(2016/10/25)

METHOD FOR PREPARING DIFLUOROACETONITRILE AND THE DERIVATIVES THEREOF
The present invention relates to a method for preparing difluoracetonitrile and the derivatives thereof. The method for preparing difluoroacetonitrile according to the invention is characterized in that it includes reacting halogenodifluoromethane and a source of cyanide anions in an alkaline medium. The invention also relates to the use of difluoroacetonitrile as an intermediate in the manufacture of difluoroacetic acid and the salts, esters, or amide thereof
-
Paragraph 0192 - 0200

(2014/02/15)

Nickel-catalyzed cross-coupling of functionalized difluoromethyl bromides and chlorides with aryl boronic acids: A general method for difluoroalkylated arenes
Transition-metal-catalyzed difluoroalkylation of aromatics remains challenging despite the importance of difluoroalkylated arenes in medicinal chemistry. Herein, the first successful example of nickel-catalyzed difluoroalkylation of aryl boronic acids is described. The reaction allows access to a variety of functionalized difluoromethyl bromides and chlorides, and paves the way to highly cost-efficient synthesis of a wide range of difluoroalkylated arenes. The notable features of this protocol are its high generality, excellent functional-group compatibility, low-cost nickel-catalyst, and practicality for gram-scale production, thus providing a facile method for applications in drug discovery and development.
Xiao, Yu-Lan,Guo, Wen-Hao,He, Guo-Zhen,Pan, Qiang,Zhang, Xingang
supporting information
p. 9909 - 9913,5
(2014/12/09)

PROCESS FOR PREPARING DIFLUOROACETIC ACID, SALTS THEREOF OR ESTERS THEREOF
A process for preparing difluoroacetic acid, salts thereof or esters thereof is described. The process can further include preparation of difluoroacetic acid, salts thereof or esters thereof, wherein the reaction occurs in the presence of water of a salt providing a fluoride anion and of monohalogenated or dihalogenated acetic acid, in acid, salified or esterified form, at least one halogen atom being other than the fluorine atom.
-
Paragraph 0101; 0102; 0103; 0104; 0105

(2013/06/04)

Highly Improved copper-mediated michael addition of ethyl bromodifluoroacetate in the presence of protic additive
Copper-mediated Michael addition of ethyl bromodifluoroacetate to Michael acceptors is accompanied by the formation of a substantial amount of byproducts. Elucidation of their structure hinted the cause of their formation, from which we discovered a highl
Kim, Bong Chan,Park, Aeri,An, Ji Eun,Lee, Hee Bong,Shin, Hyunik,Lee, Won
p. 3165 - 3170,6
(2020/08/20)

METHOD FOR PRODUCING DIFLUOROACETIC ACID ESTER
A production method of a difluoroacetic acid ester according to the present invention includes at least: a reaction step of obtaining a liquid by reaction of an alcohol represented by ROH with difluoroacetic acid fluoride (CHF2COF) in the presence of an amide compound of the following formula (1) or a sulfone compound of the following formula (2) as a hydrogen fluoride trapping agent; and a distillation step (A) of extracting a difluoroacetic acid ester represented by CHF2COOR by distillation of the reaction liquid obtained in the first step. In the present production method, there occurs no deterioration in the yield of the product due to the inherent generation of hydrogen fluoride as a by-product during the esterification reaction of difluoroacetic acid fluoride.
-
Page/Page column 9

(2012/12/13)

METHOD FOR PREPARING DIFLUOROACETIC ACID ESTERS
A method for preparing difluoroacetic acid esters is described. The method can include reacting difluoroacetyl fluorine with an aliphatic or cycloaliphatic alcohol in the presence of a heterogeneous mineral base.
-
Page/Page column 8

(2012/07/31)

BORON OR ALUMINUM COMPLEXES
The present invention relates to boron and aluminum complexes, to the preparation thereof, and to the use thereof for solubilizing ionic compounds. The complexes have one of the following formulae: in which D represents B or Al; R1 represents R, RF, NO2, CN, C(═O)OR, RSO2, or RFSO2; —X1—, —X2—, —X3— and X4 each represent a divalent group >C═O, >C═NC≡N, >C═C(C≡N)2, >CR2R3 or >SO2; —Y1—, —Y2— and —Y3— each represent a divalent group —O—, >N(C≡N), >N(CORF), >N(SO2R4), >NR4, >N(COR4) or >N(SO2RF); R, R2 and R3 each represent H, an alkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an oxaalkyl group or an alkenyl group; R4 represents an alkyl group, an aryl group, an alkylaryl group, a heteroaryl group, an arylalkyl group, an oxaalkyl group, an alkenyl group or an RFCH2— group; RF is a perfluoroalkyl group, a partially fluorinated alkyl group, or a partially or totally fluorinated phenyl group; each of the R′2 and R′3 groups represents R or F.
-
Page/Page column 24

(2011/08/02)

Processes for Production of 2-Bromo-2,2-Difluoroethanol and 2-(Alkylcarbonyloxy)-1,1-Difluoroethanesulfonic Acid Salt
Disclosed is a process for producing 2-bromo-2,2-difluoroethanol, which comprises reducing a bromodifluoroacetic acid derivative represented by the formula [1] by using an ate hydride complex as a reducing agent. 2-Bromo-2,2-difluoroethanol thus produced can be used as the starting material to carry out the esterification step, the sulfination step and the oxidation step in this order, thereby producing a 2-alkylcarbonyloxy-1,1-difluoroethanesulfonic acid salt, wherein A represents a substituted or unsubstituted linear, branched or cyclic alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 15 carbon atoms, a heteroaryloxy group having 4 to 15 carbon atoms, or a halogen atom.
-
Page/Page column 26

(2011/02/18)

METHOD FOR PRODUCING FLUORINE-CONTAINING CARBOXYLIC ACID ESTER
[Task] It is to provide a production method that the target fluorine-containing carboxylic acid ester can be obtained from a fluorine-containing ether by a one-step reaction, that a complicated step and a troublesome operation are not necessary, and that an excessive energy is not consumed. [Solving Means] A fluorine-containing carboxylic acid ester represented by the general formula R1HCFCOOR2 is produced by reacting a fluorine-containing ether represented by the general formula R1HCFCF2OR2 (R1 represents either of a fluorine atom and a C1-4 perfluoroalkyl group, and R2 represents a monovalent organic group) with water in the presence of a solid catalyst.
-
Page/Page column 8

(2010/04/24)

Ethyl difluoro(trimethylsilyl)acetate and difluoro(trimethylsilyl) acetamides - Precursors of 3,3-difluoroazetidinones
Difluoro(trimethylsilyl)acetamides 7 have been prepared from chlorodifluoroacetamides 5 by electrochemical silylation. When condensed with carbonyl compounds, they were shown to be precursors of 2,2-difluoro-3- hydroxyacetamides 8. N-(p-Methoxyphenyl)-2,2-difluoro-3-hydroxy-4- methylvaleramide (8a) has been converted into the correspending 3,3-difluoroazetidinone 9a. This new route to 3,3-difluoroazetidinones is shown to be an alternative to the one utilizing the condensation of ethyl difluoro(trimethylsilyl)acetate with imines. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Bordeau, Michel,Frebault, Frederic,Gobet, Mallory,Picard, Jean-Paul
p. 4147 - 4154
(2007/10/03)

Preparation of compounds comprising a CHF2 or CHF group
Producing compounds (I) with a mono- or difluoromethyl group from compounds (II) with a mono- or difluorohalomethyl group, where halo is bromo, iodo or preferably chloro, comprises reacting (II) with zinc in the presence of an alcohol. An independent claim is also included for an azeotropic mixture of methyl difluoroacetate and methanol.
-
Page/Page column 3

(2008/06/13)

Synthesis of N-Protected 3,3-Difluoroazetidin-2-ones
Representative N-protected 3,3-difluoroazetidin-2-ones 3 were obtained, either in one step by cycloaddition of zinc enolate 1 derived from ethyl bromodifluoroacetate onto N,N′,N″-trisubstituted hexahydro-1,3,5-triazines 2 (Schiff base trimer) in the case of 3a [N-(p-methoxybenzyl) derivative], or in two steps consisting of a Reformatsky-type reaction for the preparation of N-substituted 3-amino-2,2-difluoropropanotes 8 followed by N1-C2 cyclization under basic conditions in the cases of 3b (N-anisyl derivative) and 3c (N-benzhydryl derivative).
Lacroix, Simon,Cheguillaume, Arnaud,Gerard, Stephane,Marchand-Brynaert, Jacqueline
p. 2483 - 2486
(2007/10/03)

Non-defluorinative electrochemical silylation of ethyl trifluoroacetate: A practical synthesis of trifluoroacetyltrimethylsilane via its ethyltrimethylsilyl ketal
An efficient method for the preparation of original trifluoroacetyltrimethylsilane, CF3COSiMe3 (3), in two steps from readily available ethyl trifluoroacetate is described. Electrochemical reduction of this ester using a sacrificial anode and performed on a semimolar scale afforded the unprecedented corresponding ketal, CF3C(SiMe3)(OSiMe3)OEt (2) in 30-56% isolated yield. Treated with concentrated sulphuric acid at room temperature, the latter directly led to pure acylsilane 3 in 86% yield.
Bordeau, Michel,Clavel, Philipe,Barba, Alic,Berlande, Muriel,Biran, Claude,Roques, Nicolas
p. 3741 - 3744
(2007/10/03)

Difluoromethylation reactions of ethyl pyruvate with the TDAE - A mild approach to the synthesis of 3,3-difluoro-2-hydroxy-2-methyl-4-oxo-butyric ethyl esters derivatives
New 3,3-difluoro-2-hydroxy-2-methyl-4-oxo-butyric ethyl esters derivatives are easily obtained in moderate to good yields from the tetrakis(dimethylamino)ethylene (TDAE) mediated reduction of a series of RCF2X (X = Cl or Br) starting materials in the presence of ethyl pyruvate.
Médebielle, Maurice,Kato, Katsuya,Dolbier Jr., William R.
p. 1541 - 1543
(2007/10/03)

Preparation of difluoroacetic acid fluoride and difluoroacetic acid esters
A method for preparing difluoroacetic acid fluoride, which comprises reacting a 1-alkoxy-1,1,2,2-tetrafluoroethane of the formula HCF2 CF2 OR1 wherein R1 is a C1-4 alkyl group in a gas phase in the presence of a metal oxide catalyst.
-
(2008/06/13)

Preparation and Reaction of Difluorinated Malonaldehydic Acid Derivatives: a New Route to Functionalized α,α-Difluorinated Esters and Amides
Formylation of difluorinated Reformatsky reagents derived from chlorodifluoroacetic acid derivatives provided β,β-difluorinated N,O-acetals, which were easily converted into the corresponding ethyl hemiacetals.These compounds were found to be effective aldehyde equivalents and reacted with active methylene compounds, nitromethane, or phosphonoacetate to afford α,α-difluoro-functionalized esters and amides in good yields.
Tsukamoto, Takashi,Kitazume, Tomoya
p. 1177 - 1182
(2007/10/02)

Nickel-Catalyzed Reaction of Iodofluoroacetates with Alkenes and Zinc: A Novel and Practical Route to α,α-Difluoro-Functionalized Esters and α,α,ω,ω-Tetrafluoro Diesters
Iododifluoroacetates 1a-c react with alkenes and zinc in the presence of nickel dichloride hexahydrate in THF at room temperature or 60 deg C to give the corresponding α,α-difluoro esters in good yields.The reaction is also applicable to alkenes containing a variety of functional groups such as trimethylsilyl, hydroxy, ketone, and ester moieties.The reaction of 1 works well with dienes; the products formed depend on the length of chain of the dienes. 1,8-Nonadiene and 1,5-hexadiene afford the α,α,ω,ω-tetrafluoro diesters, while 1,6-heptadiene gave a mixture of ethyl 2,2-difluoro-8-nonenoate (19) and the cyclopentyl-substituted α,α-difluoroester 20.When diallyl ether was used as a substrate, only the tetrahydrofuran derivative 21 was formed.The nickel-catalyzed reaction can be suppressed by p-dinitrobenzene and hydroquinone.A single electron transfer initiated radical mechanism is proposed.
Yang, Zhen-Yu,Burton, Donald J.
p. 5144 - 5149
(2007/10/02)

DEFLUORATION PHOTOREDUCTIVE D'ESTERS D'ACIDES PERFLUORES: SYNTHESE D'HYDRO-2 PERFLUOROALCANOATES D'ALKYLE
Photoreduction in hexamethylphosphortriamide was found to be an efficient method to selectively reduce C-F bonds α to the carboxyl group of alkyl perfluoroesters.The reation proceeds by photoinduced electronic transfer from the excited phosphoramide.Conditions were found to remove selectively one fluorine and the reaction was applied to the synthesis of alkyl 2-hydro perfluoroesters.
Portella, C.,Iznaden, M.
p. 6467 - 6478
(2007/10/02)

ADDITION OF 1,2-DIBROMO-1-CHLOROTRIFLUOROETHANE TO CHLOROTRIFLUOROETHYLENE INDUCED BY UV-RADIATION. SYNTHESIS OF PERFLUORO-1,3-BUTADIENE AND PERFLUORO-1,3,5-HEXATRIENE
Photochemically initiated reaction of 1,2-dibromo-1-chlorotrifluoroethane (II) with chlorotrifluoroethylene (I) gave 38percent 1,4-dibromo-2,3-dichlorohexafluorobutane (III) and 19percent 1,6-dibromo-2,3,5-trichlorononafluorohexane (IV) in addition to the higher telomers.Dehalogenations of III and IV yielded perfluoro-1,3-butadiene (VI) and perfluoro-1,3,5-hexatriene (VIII) with 3-chlorononafluoro-1,5-hexadiene (VII), respectively.Photochemical reduction of butane III with 2-propanol resulted in a preferential reduction of C-Br bonds, and from 2,3-dichloro-1,1,2,3,4,4-hexafluorobutane (IX) thus formed, esters of difluoroacetic acid were prepared by dehalogenation of IX and subsequent oxidation and esterification of the product.The photochemical reduction of hexane IV gave a mixture of 79percent trichlorononafluorohexane XII and 21percent dichlorononafluorohexane XIII.The mechanism of formation of the unusual products of the title addition reaction is discussed.
Dedek, V.,Chvatal, Z.
p. 363 - 380
(2007/10/02)

THE FACILE PREPARATION OF HF FREE POLYFLUORINATED ACYL FLUORIDES
The reaction of polyfluorinated acids with the Ishikawa Reagent (FAR) in the presence of NaF gives 59 - 91 percent isolated yields of HF free polyfluorinated acyl fluorides.The reaction is rapid, safe, easily scaled up, and amenable to a one-pot procedure.
Cox, Daryl G.,Sprague, Lee G.,Burton, Donald J.
p. 383 - 388
(2007/10/02)