Perfluoroalkyl halides compounds

Solvent plays a significant role in these reactions In contrast to the formation of organocadmium compounds in the duect reaction of perfluoroalkyl iodides and cadmium powder in DMF [729], dimerization of the perfluoroalkyl halide was observed in acetonitrile [777] (equation 100)... 

The first successful syntheses utilizing trifluoromethyl iodide in transition metal chemistry were reported by Stone and his students. Stone reasoned that if CF3I would not react with transition metal anions to form trifluoromethyl derivatives [see Eq. (3)] then perhaps compounds containing perfluoroalkyl substituents could be generated by the oxidative addition of perfluoroalkyl halides to low valent transition metal substrates (9,10). The first reported trifluoromethyl-substi-tuted transition metal complex prepared by this route is shown in Eq. (4) (41). 

Perfluoroalkylmercury compounds have been prepared by reaction of perfluoroalkyl halides with cadmium amalgam or by reaction of fluoroalkenes with mercury(II) fluoride. Due to the high thermal stability of perfluoroalkylmercury compounds, they can be sublimed from concentrated sulfuric acid without decomposition and are of limited synthetic utility. These reagents have found use as difluorocarbene sources and do react with elemental sulfur at elevated temperatures to afford thioacid fluorides, di- and polysulfides, and thioketones. ... 

Inspired by M. S. Kharash s work on radical addition of CCI4 to olefins [21], the same methodology was applied to perfluoroalkyl halides [13]. It was found that the addition of these compounds to olefins could be achieved with higher selectivity and at lower temperatures in the presence of radical initiators [22] (Scheme 2.101). 

Haung, B. Liu, J. Sulfinatodehalogenation. XXVI. Perfluoroalkylation of nitrogen-containing heteroaromatic compounds with perfluoroalkyl halides and Rongalite. J. Fluorine Chem. 1993, 64(1-2), 37 16. 

Perfluoroalkylcopper compounds, derived from perfluoroalkyl halides and copper in dipolar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylacetamide, are rather stable. These complexes couple effectively with aryl and vinyl halides (Burdon et al., 1967, 1972a McLoughlin and Thrower, 1969). 

The electronegativities of perfluoroalkyl groups are so large that the perfluoroalkyl halides may be regarded, to some extent, as pseudo-interhalogen compounds. Stone and co-workers have demonstrated this analogy in the reactions between RfX and metal carbonyls, e.g. 

Table 1. Perfluoroalkylation of Carbonyl Compounds by Perfluoroalkyltin(rV) Halides [/2]...

Codeposition of silver vapor with perfluoroalkyl iodides at -196 °C provides an alternative route to nonsolvated primary perfluoroalkylsilvers [272] Phosphine complexes of trifluaromethylsilver are formed from the reaction of trimethyl-phosphme, silver acetate, and bis(trifluoromethyl)cadmium glyme [755] The per-fluoroalkylsilver compounds react with halogens [270], carbon dioxide [274], allyl halides [270, 274], mineral acids and water [275], and nitrosyl chloride [276] to give the expected products Oxidation with dioxygen gives ketones [270] or acyl halides [270] Sulfur reacts via insertion of sulfur into the carbon-silver bond [270] (equation 188)... 

Perfluoroalkyl or -aryl halides undergo oxidative addition with metal vapors to form nonsolvated fluonnated organometallic halides and this topic has been die subject of a review [289] Pentafluorophenyl halides react with Rieke nickel, cobalt, and iron to give bispentafluorophenylmetal compounds, which can be isolated in good yields as liquid complexes [290] Rieke nickel can also be used to promote the reaction of pentafluorophenyl halides with acid halides [297] (equation 193)... 

The 1,4-dinucleophilic building blocks used most are 1,2-disubstituted ethanes of the type HXCHiCHjYH, semicarbazides, thiosemicarbazides, hydroxamic acid amides, amidrazones, and 1,2-disubstituted aromatic and heteroaromatic compounds. 1,1-Dielectrophilic building blocks preferentially used are perfluorinated carboxylic acids and their derivatives, such as acid halides, anhydrides, imidoesters, nitriles, perfluoroalkyl chlorosul-... 

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