Sultones addition reactions

The reaction of two derivatives of 5,5-diallylbarbituric acid with sulphuric acid in acetonitrile is said to give characterizable 6-sultones. Addition of SO3 to hexafluorobutadiene occurs in a 1,2 manner to give (128). The double bond of (128) can be brominated to give another stable -sultone. The addition is reversible above 20 °C, and (128) reacts with excess SO3 to give (129) and SOj. ... 

The actual sulfonation reaction consists largely of a concerted 2+2 cyclo addition of S03 and a-olefin yielding a highly reactive, unstable p or 1,2-sultone that can (1) react further to give alkenesulfonic acid and (2) rearrange itself to form y- or 1,3-sultone (a fast reaction), and 8- or 1,4-sultone (a slow reaction). Possible side reactions have been identified by Bakker and Cerfontain [28]. At molar ratios of S03/olefin below 1.0 the major sulfonation product is 1,3-sultone but larger proportions of alkenesulfonic acids will be formed for ratios... 

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 only other X=Y bond involved in additions to MCP derivatives is the S=0 double bond of sulfur trioxide. Actually, the reactions of MCP (1) and BCP (3) with S03 afford exclusively the y-sultones 608 and 609 (Scheme 85) [160], formal products of [3 + 2] additions of TMM species to S=0 double bond. However, by analogy with larger methylene- and cycloalkylidenecycloalkane derivatives which give stable P-sultones at low temperature, it is presumed that... 

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... 

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. ... 

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)-... 

The formation of the sultone (160) probably involves addition of the complex across the alkene double bond, a 1,2-hydride shift and an intramolecular nucleophilic substitution reaction. The sultone (161) is formed by addition of sulfur trioxide to give the unstable p-sultone which rearranges to the more stable y-isomer (161). Another useful route to sultones is by metallation of alkanesulfonate esters for example, butane-1,3-dimethylsulfonate (162), prepared from butanel,3-diol, yields the 8-sultone, namely 6-methyl-l,2-oxathiin-2,2-dioxide (163) (Scheme 67). 

In addition to the regioselectively derivatized CDs, a number of statistically substituted CDs are in use. Highly water-soluble statistic derivatives are obtained by reaction of CDs with methyl halides [68], with epoxides (e.g., ethylene oxide, propylene oxide [69,70], or allyl glycidylether [71]), and with cyclic sulfates (e.g., butane sultone [72]). Statistical allyl ethers were converted to sulfonates by addition of sulfite [71], Monochlorotriazinyl-P-CD is another available reactive CD. Since these synthetic procedures are rather simple compared to the regioselective ones, many of these statistical compounds are available at the technical scale. 

Various aluminum hydrides have been found to induce the reductive ring opening of [2.2.1] and [3.2.1] oxabicydic compounds. Metz found that the treatment of sultone 258 with Red-Al resulted in the overall net SN2 addition of hydride and ring opening [165]. When 260 was found to also give 261 under the same reaction conditions, the mechanism postulated to account for this transformation was an initial deprotonation of the sultone 258 by Red-Al and ring opening, followed by the 1,6-delivery of hydride via aluminate 259, and stereoselective protonation, Eq. 162. 

In Chapter 27, King et al. present their work on determining reaction mechanisms for reaction of nucleophiles with sulfonyl chlorides. Many of the same phenomena observed for the more familiar nucleophilic attack at carbon are seen. Evidence is presented for pentavalent intermediates, direct displacement, elimination-addition (through sulfenes, C = S02), neighboring-group participation (through a (3-sultone), and return processes. 

The addition of catalytic amount of a Lewis acid, such as BF3, completely changes the course of the reaction of hexafluoropropene and sulfur trioxide. Allyl fluorosulfate 30 (rather than sultone 23) is the major product of the reaction in this case. The proposed mechanism of this reaction involves the formation of fluor-osulfated boron fluoride intermediate by abstracting an allylic fluorine from hexafluoropropene to form the perfluoroallyl cation, which is further stabilized by addition of -OSO2F group affording 30 (Scheme 2.15). It should be pointed out, however, that the concerted mechanism of SO3 insertion into allylic C-F bond of CF3 group also cannot be ruled out. 

Sultones are the internal esters of hydroxy sulfonic acids and sulfur analogs of lactones. The biological activities of sultones are concerned with toxicological, skin sensitization, and antiviral properties [13]. In 2009, Majumdar developed a Pd(PPh3)4-catalyzed intramolecular C-H arylation reaction of benzenesulfonic acid 2-bromophenyl esters to afford polycyclic sultones, which are generally synthesized by elimination of the corresponding hydroxyl sulfonic acid derivatives, in up to 90% yield (Scheme 3.3, path a) [14]. TBAB was found to be critical in this reaction, and no reaction occurred in the absence of this additive. An electrophilic palladation mechanism was proposed for this transformation. 

Several papers report on the nucleophilic reactivity of dithiocarbamate ions towards alkyl halides, 1,2-dibromoalkyl compounds, alkyl and aryl chloroformates, chloroacetic acid, chloroacetates, 3-halo-genophthalides, sulphenyl chlorides, sultones, and trialkylam-monium compounds. Examples of a similar reactivity of dithiocarbazate anions have also appeared. " A series of papers deal with addition or addition-elimination reactions of dithiocarbamate - or dithiocarbazate anions with w-nitrostyrene, 2-thioxo-, 2-oxo-, and 2-imino-5-methoxycarbonylmethylidene-4-thiazolidones, dimethyl acetylenedicar-boxylate, and NN -dialkyl phenylpropiolamidines. S-Monoalkylated N-cyanodithioimidocarbonates (492) underwent oxidative ring-closure to give 3-halogeno-l,2,4-thiadiazole sulphides (493) on treatment with halogenating agents. ... 

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