Radical additions to fluoro-olefins. photochemical mono-fluoroalkylation and sequential bis-fluoroalkylation of oxolane

Oxolane was fluoroalkylated by its photoadditions under atmospheric pressure. Monofluoro-alkylations were carried out with hexafluoropropene (1) and perfluorovinyl ethers C₃F₇O-[CF(CF₃)CF₂O]_n-CF = CF₂ (24, n = 0–2) by direct photoexcitation of the olefins to give high yields of addition products 9–12 (81–94%). The reactions were completely regioselecti ve at the oxolane molecule and almost completely regioselective (93–99%) at the double bond of fluoro-olefins; no bis-fluoroalkylated oxolanes were detected. The completely selective introduction of a second fluoroalkyl into position 5 of the oxolane molecule was accomplished by acetone-sensitised photoaddition of 2fluoroalkylated oxolanes 9,10 to fluoro-olefins 1 and 2. Byproducts from reactions of the dimethylketyl radical which is formed in the initiation step were isolated and have given some evidence about the reaction mechanism that is discussed.     

Synthesis of fluorine-containing benzimidazole derivatives

Various fluorine-containing benzimidazoles were obtained by the reaction of o-phenylene-diamine, 3,4-diaminotoluene, and 1,2-diamino-4-chlorobenzene with hexafluoropropene or perfluoro(methyl vinyl ether) in DMF. A new efficient method of synthesis of 2-(1,2,2,2-tet-rafluoroethyl)benzimidazole by the reaction of o-phenylenediamine with hexafluoropropene in the presence of diethylamine or dimethylamine in ethyl acetate is developed.     

Acyl Iodides in Organic Synthesis: VI. Reactions with Vinyl Ethers

Reactions of acetyl iodide with butyl vinyl ether, 1,2-divinyloxyethane, phenyl vinyl ether, 1,4-di-vinyloxybenzene, and divinyl ether were studied. Vinyl ethers derived from aliphatic alcohols (butyl vinyl ether and 1,2-divinyloxyethane) react with acetyl iodide in a way similar to ethyl vinyl ether, i.e., with cleavage of both O–Csp2 and Alk–O ether bonds. From butyl vinyl ether, a mixture of vinyl iodide, butyl acetate, vinyl acetate, and butyl iodide is formed, while 1,2-divinyloxyethane gives rise to vinyl iodide, vinyl acetate, and 2-iodoethyl acetate. The reaction of acetyl iodide with divinyl ether involves cleavage of only one O–Csp2 bond, yielding vinyl acetate and vinyl iodide. In the reactions of acetyl iodide with phenyl vinyl ether and 1,4-divinyloxybenzene, only the O–CVin bond is cleaved, whereas the O–CAr bond remains intact.     

Reactivity study of 1,1,2,4,4,5,7,7,8,8,9,9,9-tridecafluoro-5-trifluoromethyl-3,6-dioxanon-1-ene in nucleophilic reactions: fluorination properties of secondary amine adducts

A series of nucleophiles was reacted with 1,1,2,4,4,5,7,7,8,8,9,9,9-tridecafluoro-5-trifluoromethyl-3,6-dioxanon-1-ene (1) as a representative of perfluoro(alkyl vinyl ethers). All reactions were completely regioselective with the nucleophilic attack at the terminal carbon atom. Reactions of hydroxy compounds, thiols and sec-amines afforded addition products, but butyllithium, tributylphosphane or complex hydrides caused displacement of vinylic fluorine: butyllithium afforded cis-derivative, while reactions with hydrides and the phosphane led to mixtures of cis- and trans-derivatives. Diethylamine and piperidine adducts displayed the property to substitute hydroxyl for fluorine in hexadecan-1-ol. Molecular properties of hexafluoropropene and perfluoro(methyl vinyl ether) were calculated by ab initio method at the MP2/6-311G(d,p) level of theory and their impact on relative reactivity was estimated.     

Decomposition of vinyl ethers by alkalide K, K(15-crown-5)2 via organopotassium intermediates

The structure of vinyl ethers determines the direction of the C-O bond cleavage by alkalide K⁻, K⁺(15-crown-5)₂1. Highly reactive organopotassium compounds are intermediate products formed in the system containing phenyl vinyl ether, butyl vinyl ether, ethylene glycol butyl vinyl ether or triethylene glycol methyl vinyl ether. Vinylpotassium and butylpotassium react with 15-crown-5. The oxacyclic ring of the latter is opened in this case. Organopotassium ethers possessing CH₂CH₂O units eliminate ethylene. It results in various potassium alkoxides. The reaction of 1 with butyl vinyl ether occurs very slow as compared to other vinyl ethers and most of other reagents used till now.     

Lipase-catalysed selective monoacylation of 1,n-diols with vinyl acetate

A simple enzymatic methodology for the selective monoacetylation of 1,n-diols (n=5,8) using vinyl acetate is reported. Monoacetylation excesses of 81-87% at 74-90% 1,n-diol conversions were obtained in toluene and diisopropyl ether using Thermomyces lanuginosus lipase (TLL) immobilised on polypropylene powder as catalyst.     

Distribution of Perfluoro(propyl Vinyl Ether) between the Latex Based on Tetrafluoroethylene Copolymer and the Gas Phase

The distribution factors of perfluoro(propyl vinyl ether) between the tetrafluoroethylene-perfluoro(propyl vinyl ether) copolymer and the gas phase in the temperature range 20-60°C were determined by gas chromatography. From the temperature dependence of the distribution factors, the integral heats of melting and vaporization and the partial molar excess enthalpy of solution of perfluoro(propyl vinyl ether) were calculated.     

A challenge to novel fluoropolymers

Perfluoro(vinyl ether) derivatives are extremely versatile monomers in preparing a variety of functional fluoropolymers. In this paper, two challenging topics in the development of novel fluoropolymers will be introduced. Carboxylated perfluoro(vinyl ether) can be copolymerized with tetrafluoroethylene to afford perfluorinated ion-exchange membranes, which realize the innovative process for pollution-free and energy-saving chlor-alkali production. Another topic includes the discovery of selective cyclo-polymerization of specially designed difunctional perfluoromonomers such as perfluoro(allyl vinyl ether) which is readily derived from the carboxylated perfluoro(vinyl ether). The novel perfluoropolymer with a cyclic structure in the main chain is characterized by an exceptional transparency, and has been commercialized with expectation of major applications in electronics industries.     

Stabilization of water/n‐hexane emulsions by amphiphilic copolymers based on vinyl ethers and their polycomplexes with poly(acrylic acid)

Amphiphilic random copolymers based on vinyl ether of ethylene glycol and vinyl butyl ether as well as their polycomplexes with poly(acrylic acid) were studied as polymeric reagents for the stabilization of water/n‐hexane emulsions. The emulsion stability strongly depended on the content of vinyl butyl ether in the copolymers as well as their concentration in solution. The more hydrophobic copolymers stabilized emulsions more efficiently. An increase in the temperature and the addition of inorganic salts reduced the emulsion lifetime. The formation of interpolymer complexes between the copolymers and poly(acrylic acid) significantly influenced the stability of the emulsions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2625–2632, 2004     

乙腈溶液中对叔丁基杯[4]芳烃与一些脂肪胺间的相互作用

用紫外可见光谱法和电导法研究了乙腈溶液中一些脂肪胺与对叔丁基杯[4]芳烃间的相互作用。考察了它们之间的反应机理,测定了它们之间各步反应的平衡常数及表观复合常数等。由紫外可见光谱得到的表观复合常数和同一方法得到的文献值数量级相同但数值相差几倍。电导测定表明在乙腈溶液中脂肪胺与对叔丁基杯[4]芳烃间的反应分两步进行:首先胺从杯芳烃得到一个质子生成胺正离子和杯负离子,然后离子再进一步包合。其总复合常数远小于其表观复合常数。且在对叔丁基杯[4]芳烃的饱和溶解度以下,质子转移所生成的离子是反应的主要产物。结果与文献中结论相反。     

Nitrogen–Carbon Bond Formation by Reactions of a Titanium–Potassium Dinitrogen Complex with Carbon Dioxide,tert‐Butyl Isocyanate,and Phenylallene

Nitrogen–carbon bond‐forming reactions at coordinated dinitrogen in a bifunctional titanium–potassium system are reported. A titanium atrane complex with a tris(aryloxide)methyl ligand ( 1 ) was treated with two equivalents of potassium naphthalenide under N₂ atmosphere to generate a bifunctional complex ( 2 ) in which N₂ binds end‐on to two titanium centers and side‐on to three potassium cations. Dinitrogen complex 2 reacted with carbon dioxide, tert ‐butyl isocyanate, and phenylallene, forming nitrogen–carbon bonds and affording diverse N‐functionalized products. The reaction of 2 with CO₂ followed by addition of Me₃SiCl resulted in the formation of the starting complex 1 with concomitant release of silylated carboxyl hydrazines while the reaction with two equivalents of tert ‐butyl isocyanate proceeded by insertion into the Ti−N bonds. Treatment of 2 with phenylallene afforded vinyl‐substituted hydrazido complexes.     

Radical copolymerization of 2‐trifluoromethylacrylic monomers. II. Kinetics,monomer reactivities,and penultimate effect in their copolymerization with norbornenes and vinyl ethers

Radical copolymerizations of electron‐deficient 2‐trifluoromethylacrylic (TFMA) monomers, such as 2‐trifluoromethylacrylic acid and t‐butyl 2‐trifluoromethylacrylate (TBTFMA), with electron‐rich norbornene derivatives and vinyl ethers with 2,2′‐azobisisobutyronitrile as the initiator were investigated in detail through the analysis of the kinetics in situ with ¹H NMR and through the determination of the monomer reactivity ratios. The norbornene derivatives used in this study included bicyclo[2.2.1]hept‐2‐ene (norbornene) and 5‐(2‐trifluoromethyl‐1,1,1‐trifluoro‐2‐hydroxylpropyl)‐2‐norbornene. The vinyl ether monomers were ethyl vinyl ether, t‐butyl vinyl ether, and 3,4‐dihydro‐2‐H‐pyran. Vinylene carbonate was found to copolymerize with TBTFMA. Although none of the monomers underwent radical homopolymerization under normal conditions, they copolymerized readily, producing a copolymer containing 60–70 mol % TFMA. The copolymerization of the TFMA monomer with norbornenes and vinyl ethers deviated from the terminal model and could be described by the penultimate model. The copolymers of TFMA reported in this article were evaluated as chemical amplification resist polymers for the emerging field of 157‐nm lithography. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1478–1505, 2004     

Synthesis and NMR study of 9′-substituted spiroindolinonaphthoxazine derivatives

A photochromic spiroindolinonaphthoxazine derivative, 1,3,3-trimethyl-9′-hydroxy-spiro[indoline-2,3′(3H)- naphtho[2,1-b][1,4]oxazine] 3 was synthesized by condensation of 1,2,3,3-tetramethylindolenium iodide 1 and l-nitroso-2,7-dihydroxynaphthalene 2 . Further, two new derivatives, 5 and 7 , were prepared in good yields by the reactions of 3 with the hexafluoropropene trimer 4 and 4-[perfluoro(2-isopropyl-1,3-dimethyl-1-butenyl)-oxybenzoyl chloride 6 , respectively. Their unique structural features and property are discussed based on ¹H-, ¹³C- and ¹⁹F nmr spectral data.     

Polycondensation of butenediol: synthesis of telechelic 2-butene-1,4-diol oligomers

The catalytic condensation of cis-2-butene-1,4-diol with CpRu(MQA)(C(3)H(5)) (Cp = cyclopentadienyl, MQA = 4-methoxyquinoline-2-carboxylate) generates poly(2-butenediol), an unsaturated telechelic polyether diol with molecular weights between 400 and 4600 g/mol. This Ru(IV) allyl catalyst enchains 2-butene-1,4-diol primarily as the linear trans-2-butenyl ether (92%) along with vinyl branches (8%). These telechelic oligomers are useful chain extenders and macromonomers, as demonstrated by their use in the synthesis of poly(lactide)-b-poly(butenediol)-b-poly(lactide) triblock copolymers. Model studies support a proposed mechanism involving the formation of Ru(IV) allyl intermediates from allylic alcohols and chain growth by selective nucleophilic displacement at the terminus of the Ru(IV) allyl to generate trans-2-butenyl ether linkages.     

Pulse radiolysis of vinyl monomers, in the pure state and with added pyrene

Pulse radiolysis studies have been used to investigate the early phenomena in the radiolysis of acrylic acid, methyl acrylate, butyl vinyl ether, propionic acid, methyl acetate and butyl ether; the latter three solvents were used as model compounds for these vinyl monomers. The triplet state, radical cation, radical anion, and free radical of pyrene (cyclohexadienyl type) were observed to various degrees in the radiolysis of pyrene in these monomers. In acrylic acid, where the free radical and the cation dominate, the monomer polymerizes efficiently, whereas in butyl vinyl ether, where the anion dominates, polymerization does not occur. The behavior of methyl acrylate lies between that of acrylic acid and butyl vinyl ether. However, the high intensity of the electron pulses creates a high concentration of radicals leading to a short lifetime of the radical which in turn leads to a much smaller yield of polymerization. The mechanism of polymerization under high energy radiation is found to be free radical in nature.     

Living cationic polymerization of vinyl ethers with a naphthyl group: Decisive effect of the substituted position on naphthalene ring

Living cationic polymerization of a vinyl ether with a naphthyl group [2‐(2‐naphthoxy)ethyl vinyl ether, βNpOVE] was achieved using base‐assisting initiating systems with a Lewis acid. The Et_1.5AlCl_1.5/1,4‐dioxane or ethyl acetate system induced the living cationic polymerization of βNpOVE in toluene at 0 °C. The living nature of this reaction was confirmed by a monomer addition experiment, followed by ¹H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) analyses. In contrast, the polymerization of αNpOVE was not fully controlled; under similar conditions, it produced polymers with broad molecular weight distributions. The ¹H NMR and MALDI‐TOF‐MS spectra of the resultant poly(αNpOVE) revealed that the products had undesirable structures derived from Friedel–Crafts alkylation. The higher reactivity of αNpOVE in electrophilic substitution reactions, such as the Friedel–Crafts reaction, was attributable to the greater electron density of the naphthyl ring, which was calculated based on frontier orbital theory. The naphthyl groups significantly affected the properties of the resultant polymer. For example, the glass transition temperatures (T_g) of poly(NpOVE)s are higher by approximately 40 °C than that of poly(2‐phenoxyethyl vinyl ether). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

1,2‐Bis(trifluoromethyl)ethene‐1,2‐dicarbonitrile: (2+2) Cycloadditions with Vinyl Ethers

The title compound (short version: BTE) occurs in (E)‐ and (Z)‐isomers (both with b.p. of ca. 100°) which equilibrate with nucleophilic catalysts. Both undergo (2+2) cycloadditions with methyl vinyl ether at 25°. Three stereogenic centers in the cyclobutanes led to four rac‐diastereoisomers, which were obtained in pure and crystalline state. The structures were elucidated by ¹⁹F‐NMR spectroscopy and confirmed by two X‐ray analyses. The cycloadditions were not stereospecific: e.g., (E)‐BTE furnished 73% trans‐adducts (with respect to the CF₃ groups) and 27% cis‐adducts. The loss of stereochemical integrity occurs in the intermediate gauche‐zwitterions which can cyclize or rotate, but not dissociate. Under extreme conditions (2M LiClO₄ in Et₂O, 70°, 3 months), the thermodynamic equilibrium of the four cyclobutanes was achieved. Considerations of Coulombic attraction and conformational strain in the zwitterionic intermediates allow us to rationalize the observed proportions of diastereoisomeric cyclobutanes. Ethyl vinyl ether and butyl vinyl ether furnished cyclobutanes in similar diastereoisomer ratios.     

Interpolymer complexes of copolymers of vinyl ether of diethylene glycol with poly(acrylic acid)

 The complex formation reactions of poly(vinyl ether of diethylene glycol) as well as vinyl ether of diethylene glycol–vinyl butyl ether copolymers with poly(acrylic acid) have been studied in aqueous and alcohol solutions. The formation of interpolymer complexes which were stabilized by hydrogen bonds was shown. The effects of molecular weight of poly(acrylic acid) and the nature of the nonionic polymer on the composition and stability of interpolymer complexes were clarified. The critical pH values of complexation were determined for different systems with various molecular weights and hydrophobic–hydrophilic balances. The stability of the interpolymer complexes formed in aqueous and alcohol solutions with respect to dimethylformamide addition was evaluated. The role of hydrophobic interactions and the presence of active groups on stability of the interpolymer complexes is discussed. Received: 23 July 2001 Accepted: 27 September 2001     

Synthesis and hydrogel formation of fluorine‐containing amphiphilic ABA triblock copolymers

Fluorine‐containing amphiphilic ABA triblock copolymers, poly(2‐hydroxyethyl vinyl ether)‐block‐poly[2‐(2,2,3,3,3‐pentafluoropropoxy)ethyl vinyl ether]‐block‐poly(2‐hydroxyethyl vinyl ether) [poly(HOVE‐b‐PFPOVE‐b‐HOVE)] (HFH), poly[2‐(2,2,3,3,3‐pentafluoropropoxy)ethyl vinyl ether]‐block‐poly(2‐hydroxyethyl vinyl ether)‐block‐poly[2‐(2,2,3,3,3‐pentafluoropropoxy)ethyl vinyl ether] [poly(PFPOVE‐b‐HOVE‐b‐PFPOVE)] (FHF), and poly(n‐butyl vinyl ether)‐block‐poly(2‐hydroxyethyl vinyl ether)‐block‐poly(n‐butyl vinyl ether) [poly(NBVE‐b‐HOVE‐b‐NBVE)] (LHL), were synthesized, and their behavior in water was investigated. The aforementioned polymers were prepared by sequential living cationic polymerization of 2‐acetoxyethyl vinyl ether (AcOVE) and PFPOVE or NBVE, followed by hydrolysis of acetyl groups in polyAcOVE. FHF and LHL formed a hydrogel in water, whereas HFH gave a homogeneous aqueous solution. In addition, the gel‐forming concentration of FHF was much lower than that of corresponding LHL. Surface‐tension measurements of the aqueous polymer solutions revealed that all the triblock copolymers synthesized formed micelles or aggregates above about 1.0 × 10^?4 mol/L. The surface tensions of HFH and FHF solutions above the critical micelle concentration were lower than those of LHL, indicating high surface activity of fluorine‐containing triblock copolymers. Small‐angle X‐ray scattering measurements revealed that HFH formed a core‐shell sperical micelle in 1 wt % aqueous solutions, whereas the other block copolymers caused more conplicated assembly in the solutions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3751–3760, 2001     

Synthesis and characterization of original alternated fluorinated copolymers bearing glycidyl carbonate side groups

A vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as ¹H, ¹⁹F, and ¹³C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol^?1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (T_d,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012