Additives vinylene carbonate

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

Among the various additives tested, vinylene carbonate (VC) might be the most famous in the lithium ion research and development community, although the number of publications related to it seems to be rather small. Its importance can be evidenced by the number of companies that vied for the patent rights for... 

A very remote secondary H/D isotope effect has been measured for the 2 + 2-cycloaddition of TCNE to 2,7-dimethylocta-2,fran -4,6-triene. The reaction of nitric oxide with iV-benzylidene-4-methoxyaniline to produce 4-methoxybenzenediazonium nitrate and benzaldehyde is thought to proceed via a 2 + 2-cycloaddition between nitric oxide and the imine double bond. A novel mechanism for the stepwise dimerization of the parent silaethylene to 1,3-disilacyclobutane involves a low-barrier [1,2]-sigmatropic shift. Density functional, correlated ab initio calculations, and frontier MO analysis support a concerted 2 + 2-pathway for the addition of SO3 to alkenes. " The enone cycloaddition reactions of dienones and quinones have been reviewed. The 2 + 2-photocycloadditions of homochiral 2(5H)-furanones to vinylene carbonate are highly diastereoisomeric. ... 

Tetrabutylammonium fluoride, 286 Titanium(IV) chloride-Diethylalumi-num chloride, 309 Vinylene carbonate, 342 Dihydroxylation (see Addition reactions to carbon-carbon multiple bonds) Dimerization (see Coupling reactions) Displacement reactions (see Substitution reactions)... 

On the basis of these observations, Bryce-Smith et al. [115] introduced a rule stating that for addition to benzene, Pmeta when 9.6 eV < IP (alkene) <8.65 eV. They concluded that if this rule is correct, ortho addition of ethylenes to Si benzene necessarily involves an element of charge transfer to or from the ethylene. Indeed, a marked effect of polar solvents (methanol or acetonitrile) in promoting the ortho addition of benzene to ethyl vinyl ether and tetramethylethene was observed (portho increased by 20-50%, whereas cpmeta was unaffected. One exception to this rule was found by Heine and Hartmann [10], who discovered that vinylene carbonate (IP = 10.08 eV) undergoes mainly meta photocycloaddition to benzene, accompanied by some para addition. Bryce-Smith and Gilbert [46] commented that their rule referred to quantum yields and not chemical yields, whereas no quantum yields were given for the vinylene carbonate additions. Moreover, quantum yield measurements should be made at low conversions because most ortho cycloadducts are photolabile. 

Mattay et al., having discovered exciplex emission from solutions of benzene and 1,3-dioxole [122], continued their investigations with a study on selectivity and charge transfer in photoreactions of a,a,a-trifluorotoluene with 1,3-dioxole and some of its derivatives, and with vinylene carbonate and dimethylvinylene carbonate [15,143,144], a,a,a-Trifluorotoluene and 1,3-dioxole upon irradiation yield three types of products ortho cycloadducts, meta cycloadducts, and so-called substitution products (Scheme 44). The products are formed in the ratio ortho adductsimeta adducts substitution products = 0.8 1.7 0.3. The substitution reaction (which is really an addition of a C—F bond to the double bond of 1,3-dioxole, but named substitution in order to distinguish it from the ortho addition [186] is supposed to start with electron transfer from 1,3-dioxole to excited a,a,a-trifluorotoluene. The radical anion then releases a fluoride ion, which adds to the 1,3-dioxole radical cation. Radical combination then leads to the product. 

For photocycloaddition, to benzene the following conclusions were drawn from this empirical correlation [124], Olefins with poor electron-donor or poor electron-acceptor abilities yield mainly meta adducts with benzene (i.e., if AG > 1.4-1.6 eV, all other olefins yield mainly ortho adducts). Even ethene, which had seemed to behave exceptionally, fits into this correlation provided that it acts as the acceptor. The transition area from ortho to meta cycloaddition (i.e., the AG region where ortho meta = 1 1) is relatively large ( 0.2 eV). This is considered not to be surprising because the AG correlation is based on many different types of olefins. When only AG values for derivatives of 1,3-dioxole and for 1,4-dioxene were used, the transition area was narrowed to 0.03 eV. Not only ethene but also vinylene carbonate now fit into the correlation. According to the ionization potential rule, this compound should give only ortho photocycloaddition with benzene. Mattay s empirical rule predicts mainly meta addition, which is indeed found experimentally. 

The classical diene synthesis has been used for building the six-membered ring in the preparation of a/to-inositol by Criegee and Becher.36 trans, trans-Diacetoxybutadiene (XVI) and vinylene carbonate (XVII) condensed at 205-210° to an addition product (XVIII). Hydroxylation of this compound by osmium tetroxide, followed by hydrolysis, gave aWo-inositol the bulky osmium tetroxide approaches from the unhindered side of the molecule and the other possible product of the hydroxylation, m-inositol, is not formed.4 trans-Hydroxy 1 ation of XVIII would give epi-inositol. 

Chen L, Wang KE, Xie X, Xie J. Enhancing electrochemical performance of silicon film anode by vinylene carbonate electrolyte additive. Electrochem Solid-State Lett 2006 9 A512-A515. 

Abe, M., Taniguchi, K., and Hayashi, T. (2007) Exo-selective formation of bicydic oxetanes in the photocydo-addition reaction of carbonyl compounds with vinylene carbonate the important role of intermediary triplet diradicals... 

Addition of vinylene carbonate to 1,2,3,4-tetraphenylcyclopentadieneone gives 80 % of the Diels Alder addition product which upon thermolysis or photolysis yields 95 % of 2,3,4,5-tetraphenylphenol105). Other substituted alkyl-aryl-phenols are synthesized by a similar route, using 2-alkyl-3,4,5-triphenylcyclopentadienones110). 

Additional chemical stability can be given to PPVs by substitution at the vinylene carbons. Thus, CN-PPV and PPV-DP are more stable than their parent polymers [173]. Carter et al. [172] showed that a random copolymer of PPV containing non-conjugated segments is considerably more stable to photooxidation than the fully conjugated polymer. Of course, the electrical and optical properties are also altered by these substitutions. 

Because of possible relevance to mutagenesis, considerable effort has been devoted to study of the photochemical transformations of oxypyrimidines uracil, for example, takes part in a [2 -i- 2] cycloaddition with itself, or with vinylene carbonate (l,3-dioxol-2-one). Uracils undergo radical additions these too are of possible relevance to mutagenesis mechanisms. 

The impact of (2 + 2)-cycloaddition and (2 + 2)-cycloreversion reactions of heterocyclic compounds on organic chemistry over the last 10 years is clearly illustrated by several examples. Various members of the important /Hactam antibiotics, penicillin and cephalosporin C, as well as structurally related heterobicyclic compounds have been obtained by (2+ 2)-cycloaddition of heterocycles with ketenes (Section II,D,l).n Intramolecular photochemical (2 + 2)-cycloadditions of 2-pyrones yield 2-oxabicyclo 2.2.01hex-5-en-3-ones, which upon further irradiation afford cyclobutadienes (Section III,D,2).12 Intermolecular (2 + 2)-cyclo-additions of vinylene carbonates with olefins and with acetylenes offer a simple route to cyclobutanes and cyclobutenes, respectively (Sections III,B,3 and 5).13 (2 + 2)-Cycloaddition and (2 + 2)-cycloreversion reactions have contributed substantially to the development of the chemistry... 

Nitrogen-containing heterocyclic enone systems also reacted with allene to give (2 + 2)-cycloadducts, as was shown in alkaloid synthesis.178 As the keystep in the synthesis of an annotinine derivative, allene was added to 157 and the adduct 158 was obtained in quantitative yield. Various uracils have been modified by photochemical (2 + 2)-cycloaddition with olefins, e.g., vinylene carbonate,17,18° vinyl ethers, vinyl acetates, and (cetene acetals yielded 159.181 Very recently the photochemical addition of cyanoethylenes to 2-pyridones has been observed to yield mixtures of tetrahydroazocin-2-ones (160) and (2 + 2)-cycloadducts (161).182... 

Bulk polymerization of vinylene carbonate (VCA) initiated by 60Co y-rays was studied at 30°-110°C at a constant dose rate of 1 - 105 rad/hr. An overall activation energy of 5.0 kcal/mole and a maximum reaction rate of 1 10 3 mole/l-sec were obtained. As has been reported, purification of the monomer is a crucial point because inhibiting impurities are formed during the synthesis. From experiments with chlorine-substituted ethylene and vinylene carbonates, we tentatively conclude that, in addition to mono- and dichloroethylene carbonate, dichloro-vinylene carbonate is mainly responsible for the inhibition. The copolymerization behavior of VC A with some chlorine-substituted olefins was studied. Chlorotrifluoroethylene (CTFE) is an especially suitable comonomer the reactivity ratios found were rVCA = 0.42 and rCXFE = 0.48. 

The cyclic carbonate (134), produced by the addition of vinylene carbonate to phencyclone, loses CO2 on photolysis and rearranges to (135), which is the first... 

The dienophilic properties of vinylene carbonate (1,3-dioxol-2-one, 6) have been repeatedly exploited for the synthesis of cyclic polyols. Recently a number of ribofuranose derivatives have been synthesized starting from 6. The known adduct 7, obtained from 6 and furan, was c/r-hydroxylated, and after acetonation was hydrolyzed with base and cleaved with permanganate to give the dicarboxylic acid 8. The corresponding anhydride 9 gave, on treatment with trimethylsilyl azide, the isocyanate 10, which in turn was converted into the carbonate 11 on addition of methanol. The monoester 12, obtained in the reaction of anhydride 9 with isopropanol, was effectively resolved into enantiomers by the use of brucine or (/ )-l-(2-naphthyl)ethylamine. ... 

A -methylpyrrolidine to a number of ketones. When these intermediates are generated in the presence of (57 )-5-menthyloxyfuran-2[5il/]-one addition takes place to the double bond of the furanone. The adducts obtained from the addition of vinylene carbonate to such homochiral furanones have been used in a new stereoselective synthesis of butyrolactones of lyxofuranose. ... 

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