Perfluoroalkenes oxidation

The oxidation may be carried out with an inert solvent thermally (35), with a sensitizer such as bromine (36), with uv radiation (37), or over a suitable catalyst (38). Principal by-products of all these oxidation processes are the acyl fluoride products derived from oxidative cleavage of the perfluoroaLkene (eq. 

A convenient agent for the preparation of perfluoroalkene epoxides is sodium hypochlorite in a mixture with aqueous acetonitrile or another aprotic solvent cis-and tr<3 5-perfluoroalkenes are oxidized with retention of configuration [9, 10, 11, 12 13] (equation 7, Table 1)... 

Cyclic perfluoroalkenes are oxidized to the corresponding epoxides in high yields by sodium hypochlorite in aqueous acetonitrile at 0-20 C [13, 75J (equations 9 and 10) Perfluorocycloheptene gives the epoxide after 1 h in 85% yield [17] Epoxidation of perfluoro-1-methylcyclohexene is accomplished with... 

PerfluoroaUcenes are converted to vicinal diols when no fluonne atom is present at the double bond Configurational isomers of perfluoroalkenes [29] (equations 20 and 21) are oxidized stereospecifically Perfluorbicyclo[4 3 0]non-1(6) ene gives the corresponding 1,6 diol m a 24% yield upon oxidation with potassium permanganate at 18 °C for 1 h [29]... 

The uncatalyzed hydroboration-oxidation of an alkene usually affords the //-Markovnikov product while the catalyzed version can be induced to produce either Markovnikov or /z/z-Markovnikov products. The regioselectivity obtained with a catalyst has been shown to depend on the ligands attached to the metal and also on the steric and electronic properties of the reacting alkene.69 In the case of monosubstituted alkenes (except for vinylarenes), the anti-Markovnikov alcohol is obtained as the major product in either the presence or absence of a metal catalyst. However, the difference is that the metal-catalyzed reaction with catecholborane proceeds to completion within minutes at room temperature, while extended heating at 90 °C is required for the uncatalyzed transformation.60 It should be noted that there is a reversal of regioselectivity from Markovnikov B-H addition in unfunctionalized terminal olefins to the anti-Markovnikov manner in monosubstituted perfluoroalkenes, both in the achiral and chiral versions.70,71... 

Preparation of nitronitroso dimers from a variety of straight chain alkenes has been patented. " The reactions of nitric oxide with alkenes are extremely complex (e.g. isobutylene) and are rarely usefiil. Perfluoroalkenes add nitric oxide at room temperature in the da tetraflucMoethylene gives ONCF2CF2NO (68%) the reaction with perfluoropropene is more complex. ... 

Nitrosyl hydrogen sulfate adds to aikenes at -40 C in liquid SO , in Markovnikov fashion giving 2-sulfato-oximes (37-84%).Reactions of nitrogen oxides with aikenes are usually complex, yet some have limited industrial, rather than laboratory, importance. Nitryl tetrafluoroborate in acetic anhydride at -65 to -45 C adds Markovnikov fashion to aikenes, with only fair stereoselectivity, giving 3-ni-troacetates in 36-40% yields. Nitryl fluorosulfonate adds to perfluoroalkenes in fluorosulfonic acid/ffeon-113 giving 63-92% 0-nitroperfluoroalkyl fluorosulfonates. 

The A -phosphane 1, formed in the reaction of triphenylphosphane with hcxafluoro-propene, reacts further with hcxafluoroacetone in the presence of the fluoride ion. affording triphenylphosphane oxide and perfluoro(2-methylpcnt-2-ene) (2). Formation of fluoro-A -phos-phancs underlies the method for the reduction of perfluoroalkenes which involves the reaction of an alkene with tributylphosphane and subsequent hydrolysis of the A -phosphanc formed. ... 

Fluorinated epoxides are very important synthetically. Perfluoroalkenes can be oxidized by numerous means to the corresponding epoxides. The most commonly encormtered epoxide is hexafluoropropene oxide (HFPO), which is made from hexafluoropropene and is used in the synthesis of oligomers and as a source of difluorocarbene. HFPO is a colorless, nonflammable gas, boiling at -27.4 °C it can be ring-opened easily by nncleophiles or electrophiles imder a variety of conditions. HFPO can be rearranged by flnoride ion to perfluoropropionyl flnoride and by Lewis acids snch as UO2 to hexafluoroacetone (HFA). Nncleophiles typically attack the most substituted carbon of the epoxide, freeing the oxyanion to lose fluoride or act as a nucleophile itself Some examples of HFPO reactivity are shown in Scheme 3. 

Calcium atoms are particularly reactive with organohalides, and the preparation of several RCaX species by codeposition at — 196°C of RX with Ca atoms on macroscale has been reported. Similarly, deposition with perfluoroalkenes gave high yields of oxidative-addition product. ... 

Yields are often higher with sodium hypochlorite, which reacts analogously to hydrogen peroxide, with expulsion of chloride ion. The oxidation of cis- and trans-perfluoroalkenes proceeds stereospecihcally with retention of conhguration. 2,2-Bis (trifluoromethyl)ethylene is oxidized to 2 in 65-75% yield by sodium hypochlorite with phase-transfer catalysis (PTC) using Aliquat -336. ... 

Ono, T. Henderson, P. Novel epoxidation reaction of perfluoroalkenes with trimethylamine N-oxide and iodosylbenzene. Tetrahedron Lett. 2002, 43, 7961. 

Oleophilic/oleophobic fluorinated surfactants without a hydrophile, designed for use in hydrocarbon systems, are in a structural sense also nonionic fluorinated surfactants (see Section 1.8) for example, the semifluorinated alkanes [266-270], block polyethylene-polypropylene glycol ethers prepared with perfluoroalkene trimers [271], surfactants featuring an oligo(hexafluoropropene oxide) chain [272], and carboxamides and sulfonamides derived from A -(perfluorooctanesul-fonyl)piperazine [273]. 

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