Fluoroalkylations

Meagher J F, Chao K J, Barker J R and Rabinovitch B S 1974 Intramolecular vibrational energy relaxation. Decomposition of a series of chemically activated fluoroalkyl cyclopropanes J. Phys. Chem. 78 2535 3... 

An important and well studied example is the deposition of plasma-polymerized fluorinated monomer films [35], Monomers are fluoroalkyls, fluorohydroalkyls, cyclo-fluoroalkyls, as well as unsaturated species. The actual... 

FLUORINECOMPOUNDS,ORGANIC - TETRAFLUOROETHYLENE-PERFLUOROVINYLETHERCOPOLYTffiRS] (Vol 11) Per(fluoroalkyl) polyethers... 

Aromatic perfluoroaLkylation can be effected by fluorinated aUphatics via different techniques. One category features copper-assisted coupling of aryl hahdes with perfluoroalkyl iodides (eg, CF I) (111,112) or difluoromethane derivatives such as CF2Br2 (Burton s reagent) (113,114), as well as electrochemical trifluoromethylation using CF Br with a sacrificial copper anode (115). Extmsion of spacer groups attached to the fluoroalkyl moiety, eg,... 

Applications. Table 12 Hsts crop-protection chemicals and pharmaceuticals containing the aryl fluoroaLkyl ether group. 

Fluoroall l-SubstitutedTitanates. Tetraliexafluoroisopropyl titanate [21416-30-8] can be prepared by the reaction of TiCl and hexafluoroisopropyl alcohol [920-66-17, in a process similar to that used for TYZOR TPT (7). Alternatively, it can be prepared by the reaction of sodium hexafluoroisopropoxide and TiCl ia excess hexafluoroisopropyl alcohol (8). The fluoroalkyl material is much more volatile than its hydrocarbon counterpart, TYZOR TPT, and is used to deposit titanium on surfaces by chemical vapor-phase deposition (CVD). 

In contrast to the alkyl hypochlorites, the fluoroalkyl hypochlorites are extremely susceptible to hydrolysis but are much more thermally stable. Trifluoromethyl hypochlorite, eg, showed no decomposition when heated for several days at 100°C. When decomposition does occur, several products are formed C2F OCl gives COF2, CF Cl, CF COF, and GIF, whereas (GF2)3GOGl gives (GF2)2GO, GI2, GF Gl, and G2F (40). 

The fluoroalkyl hypochlorites readily react with GO and SO2 to form the corresponding chloroformates and chlorosulfates in near quantitative yields (270). They add to olefins giving a-chloroethers (271). Borate esters are obtained by reaction of perfluoroalkyl hypochlorites with BGl (272). 

Uses. /-Butyl hypochlorite has been found useful in upgrading vegetable oils (273) and in the preparation of a-substituted acryflc acid esters (274) and esters of isoprene halohydrins (275). Numerous patents describe its use in cross-linking of polymers (qv) (276), in surface treatment of mbber (qv) (277), and in odor control of polymer latexes (278). It is used in the preparation of propylene oxide (qv) in high yield with Httle or no by-products (269,279). Fluoroalkyl hypochlorites are useful as insecticides, initiators for polymerizations, and bleaching and chlorinating agents (280). 

Fluoroalkyl Acrylates—Alethacrylates—Itaconates—AIesoconates. Fluoroalkyl acrylates have been copolymerized with alkyl acrylates... 

Pyrimidine, 2-ethyl-1,4,5,6-tetrahydro-synthesis, 3, 108 Pyrimidine, 5-formyl-2-methyl-in thiamin biosynthesis, 1, 99 Pyrimidine, fluoro-syhthesis, 3, 140 Pyrimidine, 2-fluoro-NMR, 3, 63 synthesis, 3, 140 Pyriihidine, 4-fluoro-synthesis, 3, 140 Pyrimidine, 6-fluoro-synthesis, 3, 140 Pyrimidine, fluoroalkyl-synthesis, 3, 77... 

The types of polymers that are used as release coatings include silicone networks, silicone containing copolymers, polymers with long alkyl or fluoroalkyl side chains, fluoropolymers, and polyolefins. These polymers have surface energies that are less than the surface energies of commonly used PSAs, an important feature of release materials. 

Addition of carbon and fluorine can also be initiated by elettraphilic attack on a/luorinated otefin under strongly acidic conditions [250, 251, 252,253 254 255] Best known are fluoroalkylations ot tetrafluoroethylene by tertiary or highly halogenated allylic or benzylic cations in the presence of antimony pentafluoride (equation 53)... 

Diethylaminosulfur trifluoride (DAST) reacts with epoxides to give com plex mixtures in which vicinal as difluorides, gemmal difluorides, and bis(2-fluoroalkyl) ethers are the mam components I6 (equations 16 and 17)... 

Various sources of fluoride ion have been investigated, of which highly nucleophilic tetraalkylammonium fluorides ate the most effective Thuf, fluoro alkyl halides and N (fluoroalkyl)amines are efficiently synthesized by treatment of the corresponding trifluoromethanesulfonic esters with tetrabutylammonium fluoride trihydrate in aprotic solvents [5fl] (equation 34) The displacement reactions proceed quantitatively at room temperature within seconds, but tail with hydrogen fluoride-pyridine and give reasonable yields only with hydrogen fluo ride-alkylamine reagents... 

A fluorine-hydrogen migration is typical for the reactions of aldehydes branched at the carbon atom a to the formyl group. Comparable amounts of 1,1 -difluoroalkanes and 1,2-difluoroalkanes together with bis(l -fluoroalkyl) ethers are obtained [169] (equation 84). 

Aliphatic carboxylic acids react with sulfur tetrafluonde to give, in addition to 1,1,1-trifluoromethylalkanes, considerable amounts of symmetrical bis(l,l-di-fluoroalkyl)ethers. Yields of the ethers are related to the nature of the acids and to the reaction conditions. The optimum conditions for the formation of the ethers depend on their stability in highly acidic reaction medium and on the reactivity of the acids toward sulfur tetrafluonde Simple unsubstituted acids form the ethers only at low temperatures, whereas longer chain and cycloaliphatic acids give the corresponding ethers at somewhat higher temperatures Halosubstituted acids form the ethers at the relatively high reaction temperatures necessary for these reactions to proceed [203, 204, 205] (equation 101). 

Coupling reactions and related fluoroalkylations with polytTuoioalkyl halides are induced by vanous reagents, among them metals such as copper and zinc, or by an electrochemical cell. More recently, examples of carbon-carbon bond forma tion by coupling of unsaturated fluorides have been reported Both acyclic and cyclic fluoroolefins of the type (Rp)2C=CFRp undergo reducUve dimerization on treatment with phosphines [42] (equation 33) The reaction shown in equation 33 IS also accompbshed electrocheimcally but less cleanly [43]... 

A hydroxyl group in the neighborhood of fluoroalkyl is oxidized by sodium dichromate to yield a ketone [481 (equation 44)... 

The synthesis of fluoroalkyl and chloroalkyl fluoromethyl ketones is achieved by oxidation of the corresponding alcohols by sodium dichromate and sulfunc acid in methylene chlonde in the presence of a phase transfer catalyst [49] (equation 45)... 

Compounds of tnvalent phosphorus are generally oxidized to pentavalent phosphorus denvaPves bis(fluoroalkyl) and tns(fluoroalkyl) phosphites are oxi dized to the corresponding[106, lOI] (equation 92)... 

Fluoroalkyl selenides are oxidized to higher oxidation states by tert-butyl hypochlorite under the mild conditions [115] (equation 105)... 

Fluoroalkyl iodides are oxidized at the iodine atom by trifluoroperoxyacetic... 

Additions of elemental halogens to unsaturated compounds are among the most common preparations of halogenated fluoroorganics. The transformations are usually fairly clean and proceed in good yields. Besides the numerous examples of halogen addition tofluoroalkenes and fluoroalkyl-substituted alkenes, additions to perfliioropropyl vinyl ether [2] and fluormated styrenes [7, 4] have been reported. Both ionic and free-radical processes occur (equations 1 and 2)... 

Interhalogen compounds such as iodine monochloride have been added to fluoroalkyl-substituted alkenes. The observed unidirectional regiochemistry can be explained by the polarity ot the double bond [14] (equation 7)... 

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