Olefin perfluorinated

Type IV (spectators to CM) 1,1-Disubstituted olefms " 1,1-Disubstituted olefms, disub. o ,/ -unsaturated carbonyls, 4° allylic carbon-containing olefins, perfluorinated alkane olefins, 3° allylamines (protected)" Vinyl nitro olefins, protected trisubstituted allyl alcohols, a,/ -olefin of 2-subst. 1.3- butadienes, a,/ -olefm of electronically deactivated 1.3- butadienes ... 

The KF-S reaction presumably involves attack of a fluonnated caibanion on sulfur, whereas the S-Sbp5 reaction may involve electrophilic attack by a cationic sulfur species on the olefin under the strong Lewis acid conditions Electrophilic attack on a fluonnated olefin may also account for formation of a perfluorinated sulfide from reaction of bis(pentafluorophenyl)disulfide with hexafluoropropylene under superacid conditions [IS5] (equation 28)... 

The yields of thermal rearrangements of some perfluorinated olefins are very low The fact that perfluorocyclobutene yields perfluoro-l,3-butadiene at 650 °C only in a 12% yield [7] is due to the higher thermodynamic stability of perfluoro cyclobutene compared with the-open chain product [72 ]... 

The molecular ions of perfluorinated olefins are usually observed. The m/z 31 ion is frequently more abundant in fluorinated olefins than in fluorinated saturated compounds. 

The choice of the desired CM-partner directly influences the choice of the catalyst [147], Comparing the GII and the HII catalysts shows that the latter has access to a much broader spectrum of cross-partners [148], It is possible to use electron deficient cross-partners like acroleine, perfluorinated olefins, acrylonitrile, or other o / -unsaturated carbonyls, whereas GII leads to no reaction or very low conversions due to side-reactions in these cases. 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

Pesek, J., Matyska, T., and Hemphaelae, H., HPLC evaluation of mono-ol, butylphenyl and perfluorinated columns prepared via olefin hydrosilation on a silica hydride intermediate, Chromatographia, 43(1/2), 10, 1996. 

Perfluorinated hydrocarbons are much weaker eluents ilthan aliphatic hydrocarbons and they can have negative e" values. They are"useful for separating nonpolar sample components such as aliphatic >ydrocarbons, olefins, and benzene. However, their limited solubility fof the higher alkanes (> C,() and their high cost limits their use as eluents, particulariy because the separation of such samples can also be porjbrmed by gas chromatography. ... 

SCHEME 139. Oxidation of olefins to ketones with palladium catalyst 215 in a perfluorinated solvent... 

In a recent review, Tao etal. [34] describe the partial fluorination and the perfluorination of organics with particular emphasis on medically important compounds and pharmaceuticals. The selective electrofluorination (SEF) of olefins and active methylene groups is reviewed by Noel et al. [35] In the case of heterocycles, nuclear fluorination is known to be the predominant process. However, in aromatic compounds, nuclear substitution as well as addition proceeds simultaneously, leading to the formation of a mixture of products. The influence of solvents, supporting electrolytes, and adsorption on product yield and selectivity is summarized and evaluated. Dimethoxyethane is found to be a superior solvent for SEF processes. Redox mediators have been employed to minimize anode passivation and to achieve better current efficiencies. 

Type II (slow homodimerization) Styrene, allylstannanes" Styrene, 2° allylic alcohols, vinyl dioxolanes, vinyl boronates Styrenes (large ortho substit.) " " 2° allylic alcohols, vinyl epoxides, unprotected 3° allylic alcohols, acrylates, acrylamides, acrylic acid, acrolein, vinyl ketones, vinyl boronates perfluorinated alkane olefins ... 

Ionomers - pONOMERS] (Vol 14) - [OLEFIN POLYMERS - POLYETHYLENE - LOW DENSITY POLYETHYLENE] (Vol 17) -in food packaging FOOD PACKAGING] (Vol 11) -perfluorinated FUEL CELLS] (Vol 11)... 

Fluorinated carbocations play an important role as intermediates in electrophilic reactions of fluoroolefins and other unsaturated compounds. For example, F-allyl cation 1 was proposed as a reactive intermediate in reactions of HFP with fluoroolefins catalyzed by Lewis acids [7]. The difference in stability of the corresponding allylic cations was suggested as the explanation for regio-specific electrophilic conjugated addition to CF2=CC1CF=CF2 [11]. Allylic polyfluorinated carbocations were proposed as intermediates in the reactions of terminal allenes with HF [53] and BF3 [54], ring-opening reactions of cyclopropanes [55], Carbocations are also an important part of the classic mechanism of electrophilic addition to olefins (see Eq. 2). This section deals with the questions of existence and stability of poly- and perfluorinated carbocations. 

Reactivity of nitrosonium fluorosulfate and trifluoromethansulfonate 0N0S02X (X=F, CF3) is similar to that of nitronium fluorosulfate, although they are less active than the latter. Reaction, which occurs only with fluoroethylenes and perfluorinated vinyl ethers [ 119 -121 ], is of an electrophilic nature it results in low to moderate yields of nitrosoalkyl compounds when the olefin has a limited contact time with the reaction mixture ... 

The most abundant oligomer is the pentamer. These perfluorinated olefins are not reactive since the double bond is internal in the chain. However, the ICI Company [64] functionalises these alkenes by adding phenol onto the perfluorinated olefins ... 

Tetrafluoroethylene is obviously the most used monomer in telomerisation because of its good ability to polymerise (by comparison to other monomers), its low price and the properties of the obtained perfluorinated chains. Furthermore, such an olefin is symmetrical and does not lead to problems of regio-selectivity and defects in chaining. However, it is the most difficult to handle owing to its hazardous behaviour towards oxygen and pressure. 

All of these species (XIV, XV) have been for the most part applied towards function in the olefin polymerization arena use of these novel anions for the stabilization of other electrophilic species remains to be explored. Recently, the imidazolide anion XVI, as well as the perfluorinated tetraaryl borate derived from the diborane IX of Chart 2, have been used to stabilize iodonium cations.222 These cations are used as photoinitiators for cationic polymerization of epoxy resins in photolithography applications. While use of the [B(C6F5)4] led to a breakthrough in this area of research,223 higher activities are observed for more WCAs. 

At the end of considerations of the role of alkylaluminoxanes as activators for metallocenes as Ziegler-Natta olefin polymerisation catalysts, it should be noted that the analogy between methylaluminoxane and simple acidic moieties does not appear to hold. For example, highly Lewis acidic perfluorinated boranes, such as Bf CgFs, show enhanced activity as activators when compared with [Al(Me)0]x, but the stability of the resulting zirconocene-based catalyst is drastically lower than that of the catalyst formed with [Al(Me)0]x [98]. 

Perfluorinated phenylboranes and perfluorinated phenylborates are well-established activators in the metallocene-initiated polymerization of olefins. With the increasing commercial importance of metallocene technology for the polymerization of ethylene and the copolymerization of ethylene and 1-alkenes, perfluorinated phenylboranes and perfluorinated phenylborates became more readily accessible. As a consequence, a few studies on the influence of these highly fluorinated activators on Nd-catalysis are available in literature. 

Two other interesting papers should also be mentioned. Perfluorination of porphyrin was achieved with AgF resulting in a robust catalyst (equation 41), capable of performing around 50 cycles of benzene oxidation or olefin epoxidation with H20281. The second work deals with photolytic reactions of AgF in the presence of Ti02. The formally nucleophilic fluoride behaves as an electrophile and replaces protons in quite a few cases (equation 42)82. 

Oxidation of the corresponding olefins by oxygen in the presence of initiators in an inert solvent at elevated temperatures leads to the formation of perfluorinated epoxides (00RP2157805). The initiators are either halogens, trifluoromethylhypofluorite, and tetrafluoroethylene in amounts of 1.0-15.0 v/o% or free-radical producers (94ZOR309). 

Perfluorinated olefins containing an azido group at the double bond undergo transformations in at least two ways. First, under UY irradiation... 

B C6 H4(S i IVIc2C H2C H2C6F13)-/) 4]. was employed in hydrosilylation of olefins with a perfluorinated rhodium catalyst.1971... 

This route is especially valuable for the transformation of electron-rich heteroaromatic compounds into their fluorinated analogues, which are not suitable for the nucleophilic exchange route. The method has been extended by addition of fluorinated olefins. The fluoroolefins add in a radical process to the 2-position of tetrahydrofuran, followed by perfluori-nation to give the perfluorinated 2-alkyl-substituted tetrahydrofurans in excellent yields [84JFC(25)523 85JFC(29)323] (Scheme 3). 

Pyridinium (trifluoroacetyl)methylide forms [3-1-2] cycloadducts with a wide variety of perfluorinated and partially fluorinated olefins, alkynes, and nitriles [86JFC(34)275]. Photolysis of a mixture of hexafluoro-3-diazobutan-2-one and perfluoro-2-butyne in the gas phase results in the formation of tetrakis(trifluoromethyl)furan a ketocarbene is the key intermediate of this reaction sequence (87JOC2680) (Scheme 79). 

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