Diphenyl sulfonium

Garcia, B A, Gin, D Y, Dehydrative glycosylation with activated diphenyl sulfonium reagents. Scope, mode of C(l)-hemiacetal activation, and detection of reactive glycosyl intermediates, J. Am. Chem. Soc., 122, 4269-4279, 2000. 

Several examples of the alkylation of sulfur ylides are known. " " This reaction is particularly useful for the synthesis of j-alkyl diphenylsulfonium salts which cannot otherwise be prepared from diphenyl sulfide, 5-alkyl iodides and silver tetrafluoroborate, since the latter reaction usually leads to a mixture of regioisomeric sulfonium salts. Diphenylsulfonium methanide on reaction with [ C]methyl iodide allows the synthesis of [ C]isopropyl diphenyl sulfonium salt which has been used for the synthesis of [ C]-2,3-epoxysqualene (Scheme 130, entry a). This reaction unfortunately is not general... 

The carbonyl group in cyclopropyl methyl ketone was converted into two C-C single bonds on treatment with cyclopropyl(diphenyl)sulfonium bromide under basic conditions to give 2-cyclopropyl-2-methylcyclobutanone in 86% yield. ... 

CF3SO3 (4-tert- butylphenyl)diphenyl-sulfonium triflate 238... 

Aziridination of trans- and cis- 8-methylstyrene with benzy-lainine gave two diastereomeric aziridines with almost the same yields and diastereomeric ratio (1 1), suggesting that the stereochemistry of aziridines is not influenced by the olefin configuration. A one step protocol can also be appUed in case of unstable 2-arylethenyl(diphenyl)sulfonium salts. 

Synthesis of j8,y-Unsaturated Amines. 1,1-Disubstituted alkenes can be converted into the corresponding 8, /-unsaturated amines, valuable synthons in medicinal chemistry, and versatile synthetic intermediates, via a three-step protocol with moderate to good yields. The initial formation of a, 8-unsaturated diphenyl-sulfonium triflates from alkenes, such as a-methylstyrene, and the combination of diphenyl sulfoxide and TfzO, is followed by double bond migration to form /3,y-unsaturated sulfonium triflates. Subsequent nucleophilic substitution with primary or secondary amines such as fert-butylamine leads to the corresponding p,y-unsaturated amines (eq 10). ... 

The proposed mechanism of the oxidative cleavage of S-protecting groups by the chlorosilane/sulfoxide procedure is outlined in Scheme 8. 95 The first reaction is considered to be formation of the sulfonium cation 9 from diphenyl sulfoxide (7) and the oxygenophilic silyl compound 8. The formation of a sulfonium ion of this type is known and has been utilized for the reduction of sulfoxides. 97 Subsequent electrophilic attack of 9 on the sulfur atom of the S-protected cysteine residue leads to the formation of intermediate 10, whereby the nature of the silyl chloride employed should be the main factor that influences the electrophilicity of 9. The postulated intermediate 10 may then act as the electrophile and react with another S-protected cysteine residue to generate the disulfide 11 and the inert byproduct diphenyl sulfide (12). This final step is analogous to the reaction of a sulfenyl iodide as discussed in Section 6.1.1.2.1. 

Als Nukleophile werden primare und sekundare Amine bei der Reaktion mit Diphenyl-methyl-sulfonium-perchlorat in Acetonitril in Gegenwart von festem Kaliumcarbonat N-methyliert. Das Sulfonium-Salz dient bei dieser Zweiphasen-Reaktion gleichzeitig als Pha-sentransfer-Katalysator. Bei Anilin als primarem Amin erfolgt sowohl Mono- als auch Dimethylierung aus N-Methyl-anilin erhalt man in maBigcr Ausbcute N,N-Dimethyl-anilin (57%)4 ... 

Methylbis(methylthio)sulfonium hexachloroantimonate ([CH3S(SCH3)2][SbCl6]) was isolated from the reaction mixture at -40°C by the oxidation of nonpoly -merizable dimethyl disulfide [86], This result suggests that the phenylbis(phenyl-thio)sulfonium cation is produced by the oxidation of diphenyl disulfide in the acidic reaction mixture [87-89], This cation acts as the active species for the polymerization and electrophilically reacts with the / -position of the benzene ring to yield PPS [90],... 

The cationic polymerization of styrene sulfide has been reinvestigated by Van Craeynest (15). With triethyloxonium tetrafluoroborate as initiator, a rapid and quantitative polymerization was observed, followed by a slow degradation of die polymer to a mixture of cis and tram 2,5-diphenyl-l, 4-dithiane and as and tram 2,6-diphenyl-1,4-dithiane. Since the BF4 counter ion is not capable of forming a covalent bond, a back-biting reaction via sulfonium ions seems the plausible mechanism for the dimer formation. The polymerization initiated with dimethyl sulfate showed the same characteristics a fast polymerization is followed by degradation to the same mixture of isomeric diphenyl- 1,4-dithianes. However, the mwts-2,5-diphenyl derivative was the only isomer that crystallized from the solution. It is therefore reasonable to accept that with dimethyl sulfate also, the cyclic dimers of styrene sulfide are formed by a back-biting type of degradation of the polymer and not by the mechanism shown above. 

Aryl tellurium trihalides accept halide ions from tropylium bromide, ammonium halides, phosphonium halides, arsonium halides, sulfonium chlorides, telluronium chlorides, and diphenyl iodonium chloride to form aryltetrahalotellurates(lV)1-5. 

The phenyl bis(phenylthio) sulfonium cation, 203, was detected by, 3C NMR analysis of a reaction mixture of diphenyl disulfide and SbCl5 in CH2CI2 at -40° C. No signals due to radical species were detected by ESR. The generation of 203 in the presence of excess diphenyl disulfide leads only to the formation of trimer 205 (Fig. 32). The equimolar addition... 

Figure 32 Evidence of a stepwise polymerization mechanism by the formation of trimer 205 upon treatment of the phenyl bis(phenylthio) sulfonium cation with excess diphenyl disulfide. (From Ref. 115.)...

Sulfonium Diphenyl-methyl- Ell, 424f. (N-Methylier.), 459 (N-Arylier.)... 

The achiral reaction with diphenyl vinyl sulfonium triflate 73 (Table 8) has been extended to an asymmetric process in the synthesis of five- and six-membered tings, using the chiral vinyl sulfonium salt 74, with very good levels of asymmetric induction being achieved (Table 8) <2006AGE7066>. 

Pyridinium, phosphonium, arsonium and sulfonium acyl ylides all react with diphenylcyclopropenone to give 3,4-diphenyl-a-pyrones (equation 61) These reactions are assumed to be initiated by attack of the acyl oxygen on the cyclopropenone. 

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