5 -Fluoro 5 -sulfones

The lack of any difference in the rate of isomerization between fluoro-sulfonic acid solutions of 34 which had been thoroughly degassed, and those which were saturated with oxygen, suggests that the reaction does not proceed via a triplet mechanism. In fluorosulfonic acid no unproton-ated acid is detected, ruling out the possibility of n,7r excitation. Thus, there is little doubt in this case that it is the Tr,Tr singlet state which is the reactive species. Experiments carried out with a variety of methyl-substituted protonated cydohexadienones have likewise ruled out the... 

Synthesis of 2-Benzyl-l,5-dimethyltetrazoliumfluorosulfonate (115b). 189 An equimolar mixture of acetonitrile and methyl fluoro-sulfonate was kept... 

Exchange studies were carried out by solvolysing a series of butyl chlorides in 2m solutions of antimony pentafluoride in fluoro-sulfonic acid at —50° and —78°. The acid contained tracer levels of TjO and small amounts of water to provide sufficient nucleophiles to catalyse proton exchange reactions with some of the intermediates formed in the butyl system (Kramer, 1970, 1973). 

Fluorine is used for the fluorination of sites x to sulfoxides with simultaneous oxidation of the sulfoxide moiety to a sulfone. The electrophilic fluorine attacks the electron lone pairs of the sulfur atom with a consequent loss of hydrogen fluoride forming an S-fluorosulfoxy alkene. A second molecule of fluorine adds across the newly formed double bond resulting, after hydrolysis, in an a-fluoro sulfone 12.88 This reaction is used for the construction of a fluorocy-clopropane derivative 13 which is essential in the synthesis of one of the most promising members of the quinolinecarboxylic acid antibiotics.89... 

In general, fluorinated sulfonic acids can be used as catalysts for various cationic cychzations Typical examples are the triflic acid catalysis in the double cyclization of 5/,N-dibenzylpropynylarnine [82] (equation 30) and the fluoro-sulfonic acid catalyzed condensation of phenylacetaldehyde [53] (equation 31)... 

The higher reactivity of chlorin C-5 and C-20 is generally observed in electrophilic substitution reactions such as nitration, halogenation, formylation and acetoxylation. However, N-methyl- and Ar,Ar, Ar"-trimethylchlorin are formed by the SN 2 attack of the inner nitrogens on methyl fluoro-sulfonate and methyl iodide (heating in a sealed tube) respectively. 

The first member of this family - vinylidene fluoride - readily adds fluoro-sulfonic acid, even in the absence of the catalyst, and it is nitrofluorinated by a HNO3/HF mixture six times faster than CFH=CF2 [15] however, HF/HS03F superacid does not react at ambient temperature with C1CF=CF2 or CF2=CF2. These two olefins show a similar reactivity in electrophilic reactions. Interaction of polyfluorinated propylenes CF2=CXCF3 (X=H,F) with trifluoro- and tetra-fluoroethylenes proceeds at room temperature in the presence of a Lewis acid catalyst to give the corresponding polyfluoropentenes-2 ... 

Barium chloride sulfuryl chloride Barium fluoro sulfonate sulfuryl chloride Bensultap thiocyclam Benzalacetone warfarin... 

Fluorophenyl, 4 fluorophenyl, ketone flutriafol Fluoro sulfonic acid sulfuryl fluoride... 

Esters of very strong protonic acids (trifluoromethanesulfonic, fluoro-sulfonic, perchloric), however, are sufficiently strong alkylating agents to initiate the polymerization of even weakly nucleophilic monomers (cyclic acetals, ethers) [2-6], Also their anhydrides (e.g., triflic anhydride) are efficient initiators. This last compound is especially interesting, because in the polymerization of cyclic ethers it leads to macromolecules with two identical growing chain ends (difunctional initiator) [30] ... 

The replacement of a hydrogen atom on an aromatic nucleus by the sulfonyl halide grouping in a one-step process is accomplished by treat-ing the aromatic compound with chloro- or fluoro-sulfonic acid. Two equivalents of the halosulfonic acid are required, and frequently three equivalents are used. The aromatic sulfonic acid is presumably an intermediate in the process and is converted to the sulfonyl halide by the second equivalent of halosulfonic acid (cf. method 540). Reaction usually occurs at -5° to 30° in chloroform or carbon tetrachloride solution. 

Alkylation. The ketone (I) undergoes base-catalyzed O-alkylaiion by the reagent to give (2 7-mcthoxybicyclo[4.2.2]deca-2.4,7,9-tetraene) in 93-95% yield. Thus treatment of (1) with potassium t-butoxide (3 eq., 4 min.) and then with methyl fluoro-sulfonate (3 eq., 3 min.) in HMPT at 5° gives (2) in high yield. Significant C-alkylation is observed in less polar environments. 

DETHIOACETALIZATION Methyl fluoro-sulfonate. Sulfuric acid. 

ALKYLATION Benzyltriethylammonium chloride. n-Butyl mercaptan. Dialkylcar-bonium fluoroborates. Diethoxycarboni-um fluoroborate. Dimethylcopperhthium. Ethyl vinyl ether. Dimethylformamide dimethyl acetal. Dimethyl sulflde. Dimeth-ylsulfonium methylide. Ethyl chlorofor-mate. Hexamethylphosphoric triamide. Lithium diisopropylamide. Lithium N-iso-propylcydohexylamide. O-Methyldiben-zofuranium fluoroborate. Methyl fluoro-sulfonate. Naththalene-Sodium. Palladi-um(II) chloride. 1,2,2,6,6-Pentamethyl-piperidine. Potassium hydroxide. Silver oxide. Sodium bis-2-methoxyethoxyalu-minum hydride. Sodium hydride. Thal-lous ethoxide. 

Dimethyl-[l-methoxy-2,2,3,3-tetra-methyl-cyclopropyl]- -fluoro-sulfonate 1666... 

Maximum effort has been directed toward the use of solid acid catalysts. In fact, heterogeneous catalysts can be easily separated from the reaction mixture and reused they are generally not corrosive and do not produce problematic side products. Different classes of materials have been studied and utilized as heterogeneous catalysts for Friedel-Crafts acylations these include zeolites (acid treated), metal oxides, and heteropoly acids already utilized in hydrocarbon reactions. Moreover, the application of clays, perfluorinated resinsulfonic acids, and supported (fluoro) sulfonic acids, mainly exploited in the production of fine chemicals, are the subject of intensive studies in this area. 

Although unaffected by water, SO2F2 is hydrolysed by concentrated aqueous alkali. A series of sulfuryl fluorides is known, including FSO2OSO2F and FSO2OOSO2F. The latter compound is prepared by reaction 15.61 fluoro-sulfonic acid (see Section 8.9) is related to the intermediate in this reaction. 

The abnormally high heat of neutralization, 14.46 kcal/mole, of fluoro-sulfonic acid 326) has not been fully explained. 

At higher temperatures N-prenylated products were also obtained. The thia-Claisen reaction itself was initiated by S-methylation of 123 employing methyl fluoro-sulfonate (Scheme 24). 

The generation of stable carbonium ions from longifolene in fluoro-sulfonic acid has been investigated 64). The structure of the carbonium ion and consequently that of the end product was shown to be temperature dependent (Chart 13). The activation energies for the rearrangement of cations involved have been estimated to be in the range 15—20 Kcal/mol. 

Anhydrides of super acids such as trifluoromethane sulfonic acid or fluoro-sulfonic acid 5deld two active ends (298,299). 

Alkylations thus may proceed under typical organic conditions making use of alkylators such as methyl iodide, dimethyl sulfate, or methyl fluoro-sulfonate or they may proceed under biological conditions with S-adenosyl methionine and an appropriate enzyme catalyst. However, with the use of potent alkylators in stoichiometric excess, it is possible to alkylate amino acids and proteins under physiological conditions. Such provides the basis for a number of important biochemical probes and pharmacologically active substances. 

A refers to ooncenbrated sulfuric acid B, to oleum C, to chloroeolfwdc acid and D, to fluoro sulfonic arid. 

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