Intermediates 3-sultone

Boron trifluoride-triethylamine effects a ring-opening elimination of 4,4-difluoro-3-trifluoromethyl-l,2-oxathietane 2,2-dioxide to give fluorosulfonyl-trifluoromethylketene. Eliminations occur from intermediate 3-sultones, obtained by addition of sulfur trioxide to alkenes, to give alkenesulfonic acids. ... 

The intermediate 3-sultone 508, obtained by addition of sulfur trioxide to l-ethoxy-l-trifluoromethyl-2,2-difluoroethylene, decomposes to a 3-ketosulfonate ester. A similar reaction is observed with 4-(l,2-dibromo-l,2,2-trifluoroethyl)-... 

Conditions for hydrolysis (82) of the intermediate sultone mixture also help modify the ratio of alkenesulfonate to -hydroxyalkanesulfonate, distribution of alkenesulfonate positional isomers, and completeness of conversion. Caustic hydrolysis using a slight stoichiometric excess of base is employed to ensure alkaline conditions throughout the hydrolysis phase of AOS production. The rate of hydrolysis depends a great deal on temperature. The 5-sultone requires the most time for conversion to 4-hydroxyalkanesulfonate. P-Sultones and y-sultones hydrolyze so rapidly to 2-hydroxyalkanesulfonate and 3-hydroxyalkanesulfonate that temperatures below 100°C can be used. 5-Sultone completely hydrolyzes between 120 and 175°C in 1—30 minutes. The quaUty of the final product mixture is ultimately determined by the choice of conditions. 

Grummt, U. W. Reversible photoisomerizations of sulfonephthalein indicator dyes. in. Kinetic analysis of the intermediate sultone formation. J. Prakt. Chem. 1984, 326, 910-916. 

Reaction of an alkene with an excess of SO3 gives a cyclic sulfonate-sulfate anhydride, also referred to as carbyl sulfate or pyrosulfate (eq 5). This carbyl sulfate is formed by a slow insertion of SO3 into the intermediate -sultone. The complex of sulfur trioxIde with dimethyl sulfide reacts with alkenes and alkynes to afford sulfobetaines in good yields (eq 6). These sulfobetaines are produced by nucleophilic attack of the dimethyl sulfide on the initially formed -sultones. 

Proton and NMR were used to characterize a-olefin sulfonates and the intermediate sultones (11). While the spectra of purified fractions were studied, this technique is potentially applicable to the characterization of commercial mixtures. Characterization of sodium a-sulpho fatty acid methyl ester products has also been described (12). A C NMR... 

Cava and Schlessinger have reported the synthesis of 1,2,3-triphenyl-isoindole (65) in 78% yield from 1,3-diphenylisobenzofuran (68) hy reaction with thionylaniline (69) and boron trifluoride. The mechanism proposed for this remarkable transformation involves reaiTangement of the adduct (70) derived from thionylaniline and the isobenzofuran, to the tricyclic intermediate (71). This presumably collapses to the S-sultam (72), which yields the isoindole (65) upon extrusion of sulfur dioxide. Loss of sulfur dioxide, both from S-sultones and unsaturated S-sultams, is well documented. ... 

Isomerization of the sultone intermediate to form the desired alkenesulfonic acid Disulfonic acid formation... 

By linear free energy relation arguments, Williams et al. concluded that in the case of a five-membered ring sultone the reaction with a phenoxide was either stepwise or, if concerted, had a transition state close to the pentacoordinated intermediate. ... 

Very limited information is available through direct enzyme studies for DszA. However, its specificity for couple of possible intermediates resulting from DszC reaction has been studied. The DszA enzyme was capable of converting dibenz[c,e][l,2]oxanthiin 6,6-dioxide (sultone) as well as sultine to 2,2 dihydoxybiphenyl (DHBP), in addition to its inherent activity towards DBT sulfone. However, the relative activities were lower than the activity towards DBT sulfone (54% and 23%, respectively). The proposed pathway for this reaction is given in Fig. 2 [26,153],... 

The different stereochemical outcome observed in the opening of sultones by the action of dimethyl sulfide and by that of Me2S-SC>3 complex with the conjugated alkadienes has been considered as evidence against the intermediate formation of the sultones in the... 

Sulfuryl chloride isocyanate with 1 gave the expected )5-lactam 177 only as a minor product, the principal product being the y-lactam derivative 178. It is reasonable to assume that the 1,4-zwitterionic intermediate 176 is responsible for the formation of 177 and 178 (Scheme 39) [104,130]. Sulfonation of 1 with SO3 also proceeds with ring opening of one of the cyclopropyl groups to give quantitatively the spirocyclopropane-y-sultone 179 (Scheme 39) [76,132]. 

Sultines can be versatile synthetic intermediates for example, they undergo ring-opening reactions, alkylation, reductive desulfurization , and oxidation at sulfur to give sultones. 

A six-step synthesis of nonactic acid with excellent stereocontrol via sultone intermediates has been published (Scheme 26) <1998EJO2073>. The tricyclic sultone 107 was synthesized by a tandem esterification/cycloaddition with vinylsulfonyl chloride whereby only the fvo-adduct with fvo-Me was obtained <1989AGE202>. Next, the tandem elimination/alkoxide-directed 1,6-addition first led to a mixture of sulfones, but equilibration with catalytic... 

A sultone analog of 107 (4-Me(eq)) instead of 3-Me(eq))] is the key intermediate of the first enantioselective total synthesis of the antileukemic l,10-ji ( ti-eudesmanolides, (—)-eriolanin and (—)-eriolangin <2001EJ03669, 2006EJ01144>. 

The oxidation of 3,4-di-/i m-butylthiophene 1,1-dioxide with peracids (MCPBA or trifluoroperacetic acid) affords the corresponding sultone in only moderate yield <1991JOC4001>, though the sultine intermediate could be isolated and characterized structurally. 

Propane sultone has been used as a chemical intermediate to introduce the propyl-... 

SULFOXIDES. Sulfoxides arc compounds that contain a sulfinyl group covalently bonded at the sulfur atom to two carbon atoms. They have the general formula RSfO)R, ArS(OtAr, and ArS(Q)R, where Ar and Ar = aryl. Sulfoxides represent an intermediate oxidation level between sulfides and sulfottes. The naturally occurring sulfoxides often are accompanied by the corresponding sulfides or sultones. The only commercially important sulfoxide is the simplest member, dimethyl sulfoxide (DMSO) or sulfinylbismethatie. 

Sulfonation of allylsilanes with SO3 gives the corresponding trimethylsilyl allylsul-fonates in excellent yields. The sultone intermediate 10 has been detected (equation 7)49. 

The lithiation of the seven-membered sultone 217 with lithium iV,./V-diisopropylamide at -78 °C led to the rapid formation of the 1,3-dithietane 1,1,3,3-tetraoxide 218 in 55% yield, via the intermediate 219 (Scheme 26) <2003SL667>. 

In the former product, the SO3 has added across the unsaturation in the carbon chain, resulting in a saturated alkyl chain, with an internal hydroxyl and sulphonate and a terminal carboxylate. This mechanism probably proceeds via a sultone intermediate, with the final... 

Sulfonic acid functionalised ionic liquids may also be prepared via a zwitterionic intermediate from a Michael-type addition, as shown in Scheme 2.5.[84 85] In the first step 1-methylimidazole reacts with the sulfonic acid precusor 1,3-propane sultone to form a zwitterionic intermediate. Protonation with Bronsted acids affords ionic liquids with high purity that have proven to be highly efficient reaction media in, for example, esterification reactions.[86] Task-specific ionic liquids may also be prepared using semi-combinatorial methods.1871... 

The /J-sultone formed in the reaction of sulfur trioxide with tetrafluoroethenc itself is a key intermediate in the synthesis of Nafion polymers, which have commercial use as ion-exchange membranes. Furthermore, perfluorovinylsulfonyl fluoride (3) is transformed into mainly the /Tsultone 4 when heated with sulfur trioxide at elevated temperature. ... 

Synthesis o/eslra-l,3,5(10)-(rieiie-17-oii . Nicolaou and Barnette report that sultone 1 is metalated with KH in DME to afford a clear yellow solution of the anion 2. Alkylation of 2 with tosylate 3 followed by acid hydrolysis affords 4 as a mixture of diastereomers in 77% yield. Thermolysis of 4 affords estra-1,3,5(10)-triene-17-one (5) directly in 85% yield, probably by way of an intermediate o-quinone methide a. This sequence constitutes an exceedingly short and efficient synthesis of the steroid nucleus. 

The reaction of epoxy sulfonyl chlorides 136 with triethylamine is thought to proceed through intermediate epoxy sulfenes 137 to give the 5/7-1,2-oxathiole 2,2-dioxides 138 (Equation 26) <1998SL1411>. The interaction of phenylmethanesulfonyl chloride with triethylamine, 2,4,6-trimethylpyridine A -oxide, and an alkene probably involves epoxidation of phenylsulfene to give the hitherto unknown oxathiirane 3, 3 -dioxide (a-sultone) 139 which then adds to the alkene to afford the products 140 (Scheme 6) <2000CC189>. 

Oxathietane 2,2-dioxides (e.g., 448) are isolated in good yields from the reaction of sulfur trioxide with fluorinated alkenes, fluorinated dienes, ° and from the reaction of the sulfur trioxide donor 499 with fluorinated alkenes. Zwitterionic intermediates ( C-C-S020 ) are suggested. An explosion has been reported in the addition of sulfur trioxide to tetrafluoro-ethylene. Tetrafluoroethane /3-sultone (498) also is obtained by treatment of fluorosulfonyldifluoroacetic anhydride with antimony trichloride. ... 

Several j3-sultones are claimed to be formed by treatment of alkenes with sulfuric acid or by heating alkenesulfonic acids. Treatment of 2,2-dimethyl-1,1-diphenyl-1-propanol with concentrated sulfuric acid at room temperature is said to give 3-(l,l-diphenylethyl)-3-methyl-l,2-oxathietane 2,2-dioxide (96% yield). Treatment of sodium 3-bromo-2-hydroxybutanesulfonate with phosphorus trichloride is reported to give a low yield of 4-(l-bromoethyl)-l,2-oxathietane 2,2-dioxide.1,2-Oxathietane 2,2-dioxide is suggested as an intermediate in the reaction of /3-hydroxyethanesulfonyl chloride with trimethylamine to give the zwitterion 502. The first four-membered monocycUc sulfurane oxides 502a have been reported. 

The reaction is believed to be a chain process initiated by attack of a nucleophile (e.g., fluoride ion) on the sulfur atom. The fluorosulfonylacetyl fluorides are likely intermediates in the reaction of fluorinated 3-sultones with nucleophiles (water,hydroxide ion,900,908.928 893,898b,sosd,... 

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