Oxidation of Sulfides Sulfoxides and Sulfones

It is not necessary to prepare and isolate the sodium alkanethiolate in a separate operation. Because thiols are more acidic than water, they are quantitatively converted to their alkanethiolate anions by sodium hydroxide. Thus, all that is necessary is to add a thiol to sodium hydroxide in a suitable solvent (water or an alcohol) followed by the alkyl halide. 

The p-toluenesulfonate derived from (/ )-2-octanol and p-toluenesulfonyl chloride was allowed to react with sodium benzenethiolate (CeHsSNa). Give the structure, including stereochemistry and the appropriate R or S descriptor, of the product. 

Third-row elements such as sulfur can expand their valence shell beyond eight electrons, and so sulfur-oxygen bonds in sulfoxides and sulfones are sometimes represented as double bonds. 

When the desired product is a sulfoxide, sodium metaperiodate (NaI04) is an ideal reagent. It oxidizes sulfides to sulfoxides in high yield but shows no tendency to oxidize sulfoxides to sulfones. 

Peroxy acids, usually in dichloromethane as the solvent, are also reliable reagents for converting sulfides to sulfoxides. One equivalent of a peroxy acid or of hydrogen peroxide converts sulfides to sulfoxides two equivalents gives the corresponding sulfone. 

Peroxy acids, usually in dichloromethane as the solvent, are also reliable reagents for converting sulfides to sulfoxides. 

One equivalent of a peroxy acid or of hydrogen peroxide converts sulfides to sulfoxides two equivalents gives the corresponding sulfone. 

Phenyl vinyl Hydrogen Phenyl vinyl Water 

Prilosec and Nexium ( the little purple pill ) are widely used to treat acid reflux and prevent the damage that stomach acid can do to the lining of the esophagus. Prilosec is the racemic form of omeprazole Nexium is (S)-omeprazole. Write a structural formula for (S)-omeprazole clearly showing its stereochemistry. 

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Ohta and coworkers used a bacterium, Corynebacterium equi IFO 3730, rather than a fungus, to oxidize eight alkyl phenyl and p-tolyl sulfides to their respective sulfoxides (119, 120) of configuration R. Virtually all of the sulfur compounds were accounted for as the sum of uncreacted sulfide, sulfoxide and sulfone. The enantiomeric purities of the sulfoxides obtained were quite good and are shown below in parentheses. The formation of the allyl sulfoxides in high optical purity is noteworthy. The authors believe that the sulfoxides were formed by enantioselective oxidation of the sulfides rather than by enantioselective oxidation of racemic sulfoxides, since the yield of sulfoxides was greater than 50% in five of the ten oxidations reported (see also Reference 34). 

This early example is one of the numerous synthetic utilizations of the cycloadditions of olefins activated by sulfur atoms at various oxidation levels (vinyl sulfides, sulfoxides and sulfones = -S(0) R, n = 0,1, 2). Most of the work carried out in this field has been pertinently reviewed and discussed in a 1988 Tetrahedron Report with 204 references [485], Some specific aspects are underlined here and recent examples given. 

There has been much recent interest in difluoromethyl phenyl sulfones and sulfoximines regarding their use as difluoromethylating agents. Fluorine, proton, and carbon NMR data for these compounds, along with those of analogous sulfide, sulfoxide, and sulfonic acid are provided in Scheme 4.24. No obvious trends are observed for most of the data, the exception is as the oxidation state of the sulfur increases, the CF2H carbons become shielded. 

Imidazole- and benzimidazole-2-thiols usually exist largely as the thione tautomers. The thiol (thione) group is susceptible to alkylation (especially in alkaline media), and can be oxidized to sulfide, disulfide and sulfonic acid. This oxidation can often be carried out quite selectively by careful choice of oxidizing agent. The sulfur function can be removed with nitric acid, iron(III) chloride, hydrogen peroxide or, most commonly, Raney nickel. Alkyl- and arylthio groups can be oxidized to sulfoxide or sulfone. 

The selenium analogs of the sulfide, sulfoxide and sulfone are known, and the generic structures are 433, 434, and 435, respectively. The oxidation of these compounds is virtually identical to those observed with sulfur. The main drawback to their use is the toxicity of the selenium compounds. Selenoxides are relatively unstable and decompose at ambient temperatures, usually leading to syn-elimination. This selenoxide elimination reaction is more facile than the analogous sulfoxide elimination (0°C vs. 120°C) and is often preferred... 

Section 16 16 Oxidation of sulfides yields sulfoxides then sulfones Sodium metaper lodate IS specific for the oxidation of sulfides to sulfoxides and no fur ther Hydrogen peroxide or peroxy acids can yield sulfoxides (1 mole of oxidant per mole of sulfide) or sulfone (2 moles of oxidant per mole of sulfide)... 

Oxidation of sulfides results both in sulfoxides and sulfones, as well as starting material. 

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