2-Fluoroacrylic acid

The addition of nucleophiles to cyclic fluoroolefins has been reviewed by Park et al. [2 ]. The reaction with alcohols proceeds by addition-elimination to yield the cyclic vinylic ether, as illustrated by tlie reaction of l,2-dichloro-3,3-di-fluorocyclopropene Further reaction results in cyclopropane ring opening at the bond opposite the difluoromethylene carbon to give preferentially the methyl and ortho esters of (Z)-3-chloro-2-fluoroacrylic acid and a small amount of dimethyl malonate [29] (equation 8). 

Taguchi and coworkers175 studied the Lewis acid catalyzed asymmetric Diels-Alder reactions of chiral 2-fluoroacrylic acid derivatives with isoprene and cyclopentadiene. When a chiral l,3-oxazolidin-2-one and diethylaluminum chloride were used as the chiral auxiliary and the Lewis acid catalyst, respectively, a de of 90% was observed for the reaction with isoprene. The reaction with cyclopentadiene afforded a 1 1 mixture of endo and exo isomers with de values of 95% and 96%, respectively. The endo/exo selectivity was improved by using 8-phenylmenthol as the chiral auxiliary. Thus, the reaction... 

The Diels-Alder reaction between a 2-fluoroacrylic acid derivative of 8-phenyl-menthol (83) and cyclopentadiene shows high exo- and jr-diastereofacial selectivity (Scheme 30). The C(2) of endocyclic cross-conjugated 2-(acylamino)-l,3-dienes exerts excellent diastereofacial control on the Diels-Alder addition with electron-deficient dienophiles to produce octahydroquinolines. ... 

With the ready availability of 2-fluoro-allylic halides and a-fluoroacrylic acid derivatives, incorporation of a pendant fluorovinyl unit is easier than ever. The utility of these products is markedly enhanced by the reactivity of the fluorovinyl unit in olefin metathesis reactions. Some success has been found in cyclization reactions as shown below [83] (Scheme 36). 

Ohmori, A. Takaki, S. Kitahara, T.a-Fluoroacrylic acid esters and acid fluoride. US Patent 4,604,482, 1986. 

Synthesis of 3-fluoroacrylic acid by hydrolysis of the reaction product from the reaction of vinyl fluoride and carbon tetrabromide [90]. 

Polymerization Studies. Anionic Polymerization of Caprolactam (the use of (CFs C0)20 (ca. 2 mole %) enabled a lower reaction temperature to be employed and higher yiel and polyamide molecular weights to be obtained]. Soil-retardant Finishing of Cotton Ooth by Vapour-phase Graft Polymerization of Fluoroalkyl Acrylates. Radical Polymerization of a-Fluoroacrylic Acid and -Vinylpyrrolidone in an Aqueous Solution. Perfluoropolyether Esters of Quinones [the preparation of the title compounds by reaction of 1.5-dihydroxyanthraquinone with per-fluoropolyetheracyl fluorides, e.g. CFj-CFi-CF -O-CF(Ci )-CaPj-O-CF(CF,)-C50F, is... 

D-Fluoroacrylic acid methyl ester 9.6 Solution acrylonitrile initiator AIBN 71... 

Cosolvents ana Surfactants Many nonvolatile polar substances cannot be dissolved at moderate temperatures in nonpolar fluids such as CO9. Cosolvents (also called entrainers, modifiers, moderators) such as alcohols and acetone have been added to fluids to raise the solvent strength. The addition of only 2 mol % of the complexing agent tri-/i-butyl phosphate (TBP) to CO9 increases the solubility ofnydro-quinone by a factor of 250 due to Lewis acid-base interactions. Veiy recently, surfac tants have been used to form reverse micelles, microemulsions, and polymeric latexes in SCFs including CO9. These organized molecular assemblies can dissolve hydrophilic solutes and ionic species such as amino acids and even proteins. Examples of surfactant tails which interact favorably with CO9 include fluoroethers, fluoroacrylates, fluoroalkanes, propylene oxides, and siloxanes. 

Four fluorinated acrylates are presented in Table 4 [66, 67, 68, 69] to supplement the vmyl fluoride data Perfluoroacrylic acid [70] and methyl per-fluoroacrylate [69, 70] are both reported m the literature. The cis and trans isomers of fluoroethylenes are readily distinguished by the magnitude of their coupbng constants, with 3J trans typically more than 3 tunes the magnitude of 3J as... 

Under the heading acrylic elastomer the plastic literature has included a broad spectrum of carboxy-modified rubbers that have as a minor portion of the comonomers acrylic acid and/or its derivatives. However, in more recent usage the term acrylic elastomer is used to designate these rubbery products that contain a predominant amount of an acrylic ester, such as ethyl acrylate or butyl acrylate in the polymer chain. Fluoroacrylate elastomers are based on plastics prepared from the acrylic acid ester-dihydroperfluoro alcohols. 

A similar strategy was reported by Asahi Glass which prepared fluoroacrylic (FA) diblock copolymem used as surface active agents [117]. Acrylates containing perfluorinated groups were telomerized with mercapto acetic acid followed by the condensation of the telomer produced with polypropylene oxide (PPO) to yield PPO-t-PFA diblock copolymers. 

Of a large number of possible fluorinated acrylates, the homopolymers and copolymers of fluoroalkyl acrylates and methacrylates are the most suitable for practical applications. They are used in the manufacture of plastic lightguides (optical fibers) resists water-, oil-, and dirt-repellent coatings and other advanced applications [14]. Several rather complex methods to prepare the a-fluoroalkyl monomers (e.g., a-phenyl fluoroacrylates, a-(trifluoromethyl) acrylic and its esters, esters of perfluoromethacrylic acid) exist and are discussed in some detail in [14]. Generally, a-fluoroacrylates polymerize more readily than corresponding nonfluorinated acrylates and methacrylates, mostly by free radical mechanism [15], Copolymerization of fluoroacrylates has been carried out in bulk, solution, or emulsion initiated with peroxides, azobisisobutyronitrile, or y-irradiation [16]. Fluoroalkyl methacrylates and acrylates also polymerize by anionic mechanism, but the polymerization rates are considerably slower than those of radical polymerization [17]. 

A general method leading to the stereospecific synthesis of 3-fluoroacrylate derivatives arose from the early work of Shen et al. (37) who demonstrated that chlorodifluoromethane adds to malonate carbanions to give a-difluoromethylmalonate derivatives (Scheme 21). Bey and co-workers (38-40) made extensive use of this reaction in a major program directed towards the synthesis of a-difluoromethylamines and amino acids. A key step in these syntheses is the acid catalyzed decarboxylation of the a-difluoro-methylmalonates (70) (Scheme 22). On occasion, 3-fluoroacrylates (72) were observeJTas side-products in addition to the expected compounds (71). 

The chemistry of XV is similar to that of HFPO. It can be isomerized to an acyl fluoride with Lewis acids (Eq 13.16) but more importantly, it will react with nucleophiles to open the oxetane ring. Reaction with Nal yields an acyl fluoride that may be dehalogenated and esterified to give useful a-fluoroacrylate monomers (Eq 13.17). 

CHF CFa, from hexafiuoropropene and propene at 250 °C, the formation of addacts between ethyl a>fluoroacrylate and chlorotrifluoro- or tetrailuoro-ethylene, preparation of various 1,1,2-trifluorocyclobutanes as anaesthetics, and the formation of adducts (78 X = Y = F or Cl X = F, Y = O) from diethyl itaconate at 180 °C, where diethyl dtraconate failed to react. 2-Alkoxy-3-phenylcyclobut-2-enoiies are formed when the adducts of styrene and CF tCFCl or CFgiCFj are treated with potassium hydroxide in ethanol or potassium t-butoxide in t-butanol, respectively. The adducts of / -nitro- and p-methoxy-phenylacetylene and chlorotrifluoro-ethylene may be hydrolysed by concentrated sulphuric acid to arylcyclo-butenediones. Tetrafluoroethylene adds photochemically to 3p-acetoxy-pregna-5,16-dien-20-one by [2 + 2] addition to the C—C bond of the enone grouping and by [2 + 4] addition to this function. ... 

IMDA reactions of a-fluorinated dienyl acrylates was also a difficult reaction owing to the low reactivity of a-fluoroacrylate parts and the formation of defluorinated byproducts from the initially formed IMDA adducts under Lewis acid-catalyzed conditions. For these reactions, the authors found an effective bidentate Lewis acid (133) derived from 3,3, 5,5 -tetrabromo-l,l -biphenyl-2,2 -diol (Br4BIPOL) and... 

M03A1 (Scheme 6.130) [156]. On the basis of the substituent effects on the stereochemistry of the product, we deduced that the IMDA reaction of a-fluoroacrylates proceeds via ando-boat transition state as in the case of the corresponding non-fluorinated acrylate. Surprisingly, different from a-fluoroacrylate, a-chloroacrylate did not react even at a higher temperature with (133) and nonsubstituted acrylate (X = H) showed somewhat lower reactivity to obtain the IMDA product in 58% yield after 42 hours at 80 °C. Thus, the present aluminum Lewis acid derived from Br4BIPOL showed a significant specific activation in the IMDA reaction of a-fluoroacrylates. 

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