Perfluoroalkanesulfonyl

Simple a-fluorosulfides are reduced to the fluoroalkanes by sodium-ethanol [9J (equation 75). Clean conversion of bis(trifluoromethyl) diiulfide to trifluoromethyl mercaptan is accomplished with hydrogen sulfide and ultraviolet irradiation (941 (equation 76). Perfluoroalkanesulfonyl fluondes are converted to the sulfmate salts by hydrazine [95] (equauon 77)... 

Reduction of perfluoroalkanesulfonyl halides leads to sulfinic acids, which are unstable in aqueous acid and give perfluoroalkanoic acids [75] (equation 16) A variety of reducing agents can be used... 

Reaction of perfluoroalkanesulfonyl chlorides with aromatic compounds m the presence of dichloro bis(triphenylphosphine)ruthemum (II) gives perfluoro alkylated products [/i52] (equation 139)... 

In some cases, however, especially with shorter perfluoroalkanesulfonyl fluo rides, sulfur dioxide may be removed by antimony pentafluoride at temperatures between 20 and 90 °C depending on the substituents [99] (equation 66)... 

Perfluoroalkanesulfonyl chlorides, 2 148 Perfluoroalkoxides, of alkali metals preparation, 15 263... 

Fluorous biphase catalysis was also applied in Friedel-Crafts acylation with Yb tris(perfluoroalkanesulfonyl)methide catalysts with acid anhydrides.59 Of the aromatics studied, activated compounds and naphthalene (95% conversion) showed satisfactory reactivity. 

Hydroboration of a variety of alkenes and terminal alkynes with catecholborane in the fluorous solvent perfluoromethylcyclohexane was performed using fluorous analogs of the Wilkinson catalyst.135 136 Recycling of a rhodium-based alkene hydrosilylation catalyst was also successful.137 Activated aromatics and naphthalene showed satisfactory reactivity in Friedel-Crafts acylation with acid anhydrides in the presence of Yb tris(perfluoroalkanesulfonyl)methide catalysts.138... 

Perfluoroalkanesulfonyl fluorides are oxidized with nitrogen oxides in the vapor phase at high temperatures.9 Nitrogen dioxide gives, in several cases, good yields of perfluoroalkanecar-boxylie acid fluorides (Table 19).9 The products are usually isolated in the form of free acids. 

Phenyliodonium bis(perfluoroalkanesulfonyl)methide 200 can react with various organic substrates upon irradiation with UV light [141,142]. For example, the reaction with cyclohexene affords cycloaddition product 201, while the photolysis of 200 in benzene or toluene leads to the C-H insertion products 202 (Scheme 72) [142]. 

The synthesis of proline-fused heterocyclic systems by 1,3-dipolar cycloaddition has been well-established in solution-phase synthesis (Scheme 14) [42]. It is usually performed as a one-pot, three-component reaction of a dipo-larophile with an in situ prepared azomethine ylide. Perfluoroalkanesulfonyl protected hydroxybenzaldehydes [43] or fluorous alcohol protected amino esters [44] have been developed as two different fluorous components for the synthesis of proline derivatives 11 and 12. 

Perfluoroalkanesulfonyl protected hydroxybenzaldehydes have been used together with isonitriles and 2-aminopyridines or 2-aminopyrazines for... 

Fluorination with perfluoroalkanesulfonyl fluorides. Since triflate formation is an expensive procedure, we examined the use of an inexpensive perfluoroalkanesulfonyl fluoride such as perfluoro-1-butanesulfonyl fluoride (nonafluoro-l-butanesulfonyl fluoride, C4F9S02F, NfF) or perfluoro-1-octanesulfonyl fluoride (C8Fi7S02F, OctF) for fluorination,... 

Takamatsu, S., Katayama, S., Hirose, N., et al. (2002) Convenient synthesis of fluorinated nucleosides with perfluoroalkanesulfonyl fluorides. Nucleosides, Nucleotides, Nucleic Acids, 21, 849-861. 

Perfluoroalkanesulfonyl halides 1-35 and 1-36 induced controlled polymerization of styrene and MMA in the presence of copper catalysts, although the initiation efficiency is lower.177 With the alkanesulfo-nyl halides 1-35 and 1-36, decomposition by loss of S02 from the initial sulfonyl radical occurs to give a perfluoroalkyl radical, which then adds to the monomer to initiate the polymerization. 

Perfluoroalkanesulfonyl fluorides and of related materials are manufactured by the electrochemical fluorination of the corresponding alkanesulfonyl fluorides or cyclic sulfonesP This electrochemical synthesis results in replacement of all C-H bonds in the feedstock. The perfluorinated alkanesulfonyl fluoride products are neutralized to make the anhydrous salt, then acidified and distilled to afford the anhydrous sulfonic acid. Alkyl chain degradation in the electrochemical cell becomes more pronounced at longer chain lengths. Addition of short-chain divalent sulfur compounds (e.g., thiols, sulfides) to the cell inhibits buildup of tarry materials and loss of efficiency. 

Kresze and coworkers have found about a three order of magnitude rate increase in imino ene reactions when an N-tosyl group is replaced with an N-perfluoroalkanesulfonyl moiety [87]. Thus, with the glyoxylate ester-derived imine and the one from chloral 255 as the enophiles, reactions with acyclic olefins are very rapid and occur at room temperature [Eq. (60)]. In these ene reactions one stereoisomeric homoallylic amine 256 was typically generated, although the stereochemistry was not elucidated. However, in one reported case a 1 1 mixture of diastereomers was obtained. Mechanistic studies based upon kinetic isotope effects seem to indicate that this reaction may in fact be a two-step process rather than a concerted one [87b]. 

Ytterbium(lll) tris(perfluoroalkanesulfonyl)methides 34 are effective catalysts (10% mol) for the Friedel-Crafts acylation of arenes with anhydrides. Compounds 34 can be prepared as described in Scheme 3.7. Trimethylsilylmethyl lithium 31 is reacted with commercially available per-fluoroalkanesulfonyl fluorides, giving intermediates 32 that can similarly produce tris-perfluoroalkanesulfonyl derivatives 33. These compounds are converted into the catalysts 34 by reaction with ytterbium oxide. It is shown that the highly fluorinated catalyst (34, Ri = C5F13, = C8F17) (10% mol)... 

Barrett, A. G. M., Braddock, D. G., Gatterick, D., Chadwick, D., Henschke, J. P., and McKinnell, R. M. 2000. Pluorous biphase catalytic Priedel-Crafts acylation ytterbium tris(perfluoroalkanesulfonyl)methide catalysts. Synlett 847-849. 

The yields of the perfluoroalkanesulfonyl fluorides fall off rapidly with increasing chain length of the starting material. 

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