Sulfides diphenyl sulfoxide

Sodium permanganate and, especially, osmium tetroxide oxidize sulfoxides to sulfones but do not oxidize sulfides [837]. When a mixture of equimolar amounts of diphenyl sulfide, diphenyl sulfoxide, and osmium tetroxide is refluxed in ether for 48 h, the sulfoxide is oxidized in 96% yield to the sulfone, whereas the sulfide is completely recovered [837], Certain unsaturated sulfoxides treated with a catalytic amount of osmium tetroxide and trimethylamine oxide as a reoxidant are not only oxidized to sulfones but also hydroxylated at the double bond. The sulfoxide group exerts a steric influence in the hydroxylation two stereoisomers of a sulfoxide yield, by syn hydroxylation, two different stereoisomeric diols (equation 580) [1102]. 

Trofimov and coworkers19 studied the yields of the radicals by ESR in the radiolysis at 100-110 K of diphenyl sulfoxide and tetramethylene sulfoxide. They found for tetramethy-lene sulfoxide a higher yield of radicals (G = 1.8) than for tetramethylene sulfide (G = 0.45). 

For the case of diphenyl sulfoxide the yield of the radicals is very low (G = 0.1), not much different than for diphenyl sulfide. 

Bei der Reduktion von Dialkyl- und Benzyl-sulfoxiden mit Trichlorsilan in Ather wird ein Gemisch aus Thioacetal und Sulfan erhalten3, in der Gegenwart von a. -Wasserstoff-Atomen lauft also die Reduktion unter Spaltung und Rekombination des Molekiils ab. Dementsprechend werden Diaryl-sulfoxide in Ather praktisch quantitativ zu Sulfanen re-duziert (z.B. Diphenyl-sulfoxid zu Diphenyl-sulfid mit 98% d.Th.). 

Likewise, pyridines such as methyl isonicotinate 1999 or quinolines are readily oxidized by BTSP 1949 in the presence of HOReOs in CH2CI2 to give, after 6 h at 24°C, 98% yield of, e.g., methyl isonicotinate N-oxide 2000 [174] (Scheme 12.49). The oxidation of diphenylsulfide with BTSP 1949 and triphenylphosphine dichloride in acetonitrile results, after 60 h at room temperature, in only 12% diphenyl sulfoxide 2001 and 88% recovered diphenyl sulfide [175] (Scheme 12.49), whereas thianthrene 5-oxide 2002 is oxidized by the peroxy-Mo complex 2003 to give 58% of a mixture of 2004 to 2007 in which the trans 5,10-thioxide 2005 predominates [176] (Scheme 12.50). 

The oxidation of sulfides to sulfoxides (1 eq. of oxidant) and sulfones (2 eq. of oxidant) is possible in the absence of a catalyst by employing the perhydrate prepared from hexafluoroacetone or 2-hydroperoxy-l,l,l-trifluoropropan-2-ol as reported by Ganeshpure and Adam (Scheme 99 f°. The reaction is highly chemoselective and sulfoxidation occurs in the presence of double bonds and amine functions, which were not oxidized. With one equivalent of the a-hydroxyhydroperoxide, diphenyl sulfide was selectively transformed to the sulfoxide in quantitative yield and with two equivalents of oxidant the corresponding sulfone was quantitatively obtained. 2-Hydroperoxy-l,l,l-fluoropropan-2-ol as an electrophilic oxidant oxidizes thianthrene-5-oxide almost exclusively to the corresponding cw-disulfoxide, although low conversions were observed (15%) (Scheme 99). Deprotonation of this oxidant with sodium carbonate in methanol leads to a peroxo anion, which is a nucleophilic oxidant and oxidizes thianthrene-5-oxide preferentially to the sulfone. 

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. 

Under similar conditions, diphenyl sulfide, C6H5-S-C6H5, was found to be unreactive, indicating that the reactions listed in Table XII take place inside the pore structure, which is not accessible to bulky molecules such as diphenyl sulfide. The selectivity to sulfoxides (Table XII) is the result of a competition between sulfides and sulfoxides for the catalytic site dimethyl sulfide competes effectively, and the selectivity to sulfoxide is 97% with only 3% sulfone produced. The other reactant molecules give larger amounts of sulfones. However the reaction of dimethyl sulfide was carried out at 298 K, whereas the other sulfides reacted at the reflux temperature of acetone the temperature difference may explain part of the differences shown in Table XII. 

Osmium tetroxide is another chemoselective oxidant repotted to yield sulfones frtxn sulfoxides. Thus, treatment of a mixture of diphenyl sulfide and sulfoxide with OSO4 in boiling ether for 48 h affords di-... 

Hydrogenolysis of vinyl sulfides,vinyl sulfoxides and vinyl sulfones is rare, and may be accompanied by saturation of the double bond. Thus vinylic sulfide (29) gives only 5% of l,5-diphenyl-2-... 

Ceric ammonium nitrate (1.10 g, 0.002 mol) is added in one portion to a stirred solution of 0.093 g (0.0005 mol) of diphenyl sulfide in 8 mL of 75% aqueous acetonitrile. After 3 min at room temperature, the mixture is quenched with 5 mL of water, and the product is obtained by extraction with two 20-mL portions of ether and evaporation of the solvents. Diphenyl sulfoxide, mp 68-70 °C, is obtained in 82% yield. 

The reaction was carried out on numerous aromatic and aliphatic sulfides and sulfoxides. Among the compounds made in essentially quantitative yields were dibenzyl sulfoxide, dibenzyl sulfone, dimethyl sulfone, diphenyl sulfoxide, thionyldiglycolic acid, and carboxymethylthionylsuccinic acid (Table I). 

Diphenylsuccinic acids, 556 Diphenyl sulfide, 1122 Diphenyl sulfoxide, 348 Diphenyltelluride, 348-349 Diphenyltin, 349... 

The arylsulfonium metal halide complex salts are not readily available. Triphenylsulfoniurn hexafluorophosphate can be prepared from diphenyliodonium hexafluorophosphate by heating with phenyl sulfide, as described by Knapczyk and McEwen ( ), or by reaction of phenyl magnesium bromide with diphenyl sulfoxide followed by reaction with hexafluorophosphoric acid according to the procedure of Wildi, Taylor and Potratz (60). 

Diphenylmercury, 31 Diphenylmethane, 343 p-(Diphenylmethyl)diphenylhydroxy-methylbenzene, 454 1,8-Diphenylnaphthalene, 112 2,4-Diphenylnaphthoresorcinol, 345 9,10-Diphenylphenanthrene, 79 Diphenylphosphide, 179 p-Diphenylphosphinobenzoic acid, 179 p-Diphenylphosphinylbenzoic acid, 179 Diphenyl phosphorochlorodate, 180, 322 Diphenyl sulfide, 180, 358 Diphenylsulfonium isopropylide, 180-181 Diphenyl sulfoxide, 99... 

In an important contribution Liang et al. [92] examined the kinetics of the oxidation of diethyl sulfide in the presence of diphenyl sulfoxide and diphenyl sulfide, two molecules which react very inefficiently with 02(1Ag) themselves but undergo oxidation by some intermediate species to give the corresponding sulfone. They were able to show that, in methanol, both diphenyl sulfide... 

These NMR experiments at low temperature and the product analysis indicate that both triphenylsulfonium salt and diphenyl sulfoxide react with PhLi to give an identical tetraphenyl sulfurane 101 as a discrete intermediate at low temperature, which, on warming to room temperature, decomposes to diphenyl sulfide 102 and biphenyl 103. Interestingly, the four phenyl groups in the sulfurane 101 become spectroscopically identical, suggesting that the pseudorotation takes place rapidly even at low temperature such as -105 °C. 

Dimethyl sulfide Dimethyl sulfoxide Dimethyl terephthalate 1,4-Dioxane Diphenyl ether Dipropyl amine Dodecane Eicosane... 

Analogous chemistry was observed by Denney and co-workers11 when divalent sulfur nucleophiles were allowed to react with dioxetanes. Thus, diphenyl sulfide gave epoxide and diphenyl sulfoxide, presumably via the sulfurane (63), as shown in Eq. (50). When the ligands on the sulfur nucleophile were alkoxy groups, NMR evidence for the intermediary sulfuranes was provided. Similar results were observed by Wasserman... 

Singlet oxygen reactions. Dialkyl sulfides are oxidized to sulfoxides by singlet oxygen. Diphenyl sulfide is practically inert under the same conditions. However, if it is added to the photooxidation of a dialkyl sulfide, it is converted into diphenyl sulfoxide. The interpretation advanced by Foote and Peters is that diphenyl sulfide reacts readily with persulfoxides, formed in the reaction of alkyl sulfides with singlet oxygen ... 

The first report of the photochemistry of a conjugated aromatic sulfoxide appears to be that of Kharasch and Khodair [32]. In a study more principally aimed at the sulfones, they showed that photolysis of diphenyl sulfoxide 5-H in benzene led to biphenyl 41 (53%), diphenyl sulfide (7%), and trace diphenyl-disulfide 45. Biphenyl was also the major product of diphenyl sulfone photolysis, and it was shown to arise from attack of the photochemically generated phenyl radical on solvent (benzene). The same mechanism was clearly implied for the sulfoxide. The disulfide presumably comes from secondary photolysis of the unobserved phenyl benzenesulfenate 42. (The formation of the sulfide is addressed below in the section of deoxygenation.) Later workers showed that pyridine could be tolylated by photolysis of di-p-tolyl sulfoxide 5-Me with a product distribution quite consistent with other radical phenylations [33]. 

Under conditions of direct photolysis, the dimer mechanism is not in effect for the deoxygenation of 9. The quanmm yield, lower than that reported for 200, is invariant over the concentration range of 0.6 to 30 mM in benzene or THF. Also, the quantum yield of deoxygenation of 9 is independent of added diphenyl sulfoxide up to about 50 equivalents and no diphenyl sulfide is observed. Finally, the deoxygenation is effected even at concentrations as low as <10 M in ether/isopentane/alcohol glass at 77K [100]. 

Deoxygenation is most commonly a minor or merely competitive reaction pathway, with 9 being one of the exceptional cases in which it is an essentially quantitative reaction. The earliest examples of aromatic sulfoxide deoxygenation were those of Shelton and Posner, both with simple systems. Shelton showed that t-butyl phenyl sulfoxide 78 produced modest quantities of the sulfide on direct photolysis [14]. Methyl phenyl sulfoxide and diphenyl sulfoxide were other prototypical early examples, and a solvent dependence was suggested [97]. 

Cram reported an example that illustrates both the oxidation of sulfides to sulfoxides and the formation of diastereomers.575 Oxidation of erythro- or threo-l-alkylthio-l,2-diphenyl-propane with peroxybenzoic acid gave syn- and anti- sulfides. The erythro-sulfide (anti-sulfide 416) gave two erythro- (anti) sulfoxides, 417 and 418.575 Similarly, the threo- sulfide (syn-sulfide 419) gave two threo-(syn-sulfides, 420 and 421. The two... 

Sulfides/sulfoxide interchange. The reduction with triphenylphosphine requires the (PhjPjjRhOClj catalyst. On the other hand, the same catalyst can be used to transfer the oxygen atom of diphenyl sulfoxide to other sulfides. ... 

Diphenyl-1,4-butanedione Diphenyl sulfide Diphenyl sulfone Diphenyl sulfoxide... 

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