Sulfides dimethyldioxirane

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

TABLE 2. Comparison of the calculated barriers (kcal mol ) for the oxidation of alkenes, dimethyl sulfide, trimethylamine and trimethylphosphine with peroxynitrous add, peroxyformic acid and dimethyldioxirane (DMDO)... 

Acetyl-protected 1,2,3,4-tetrahydropyrazines 105, which are prepared by treatment of 2,3-dihydropyrazine with acetic anhydride and zinc (Scheme 27), undergo photooxidation to produce new dioxetanes 106 <1995JA9690>. Upon thermolysis, the dioxetanes 106 decompose quantitatively to tetraacyl ethylenediamines 107. Dimethyldioxirane oxidation of tetrahydropyrazine 105 affords novel epoxide 108, which is also generated by deoxygenation of dioxetane 106 with dimethyl sulfide. In 2,3,4,5-tetrahydropyrazine 1-oxide 109, which is prepared... 

The use of dimethyldioxirane in the oxidation reactions of sulfides deserves to be mentioned [83, 84] as this mild neutral oxygen transfer reagent allows, for instance, highly reactive compounds such as a-oxosulfones to be obtained. Although the oxidation can usually be controlled at the sulfoxide level by using a stoichiometric amount of the... 

Butyl hypochlorite, 55 of phenols to quinones Benzoyl /-butyl nitroxide, 28 2,3-Dichloro-5,6-dicyano-l, 4-benzoqui-none, 104 Periodic acid, 238 of phosphorus compounds Dimethyldioxirane, 120 of selenium compounds Potassium permanganate, 258 of sulfides to sulfoxides and sulfones /-Butyl hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 51 ra-Chloroperbenzoic acid, 76, 112 Dimethyldioxirane, 120 of thiols to sulfur compounds Trimethylsilyl chlorochromate, 327... 

Deoxygenation of pyridine A-oxides has been achieved using dimethyldioxiran <95CC1831> and palladium with sodium hypophosphite <95GCI(124)385>. Pyridine A-oxides, with ruthenium porphyrin catalysts, have been used as an oxidant of aromatic compounds <95JA(117)8879> or olefins, alcohols, sulfides and alkanes <95FI(40)867>. 

Determination of dimethyldioxirane concentration by the GLC method is as follows A standard solution of thioanisole (phenyl methyl sulfide) is prepared. The solution is usually 0.2 M in acetone, but other concentrations may be used. It is important to keep the sulfide in excess so that oxidation by the dioxirane will produce largely or exclusively the sulfoxide and not the sulfone. 

To determine the dioxirane concentration 1 mL each of the dioxirane, sulfide, and internal standard solutions are combined in a vial. The GLC analysis is then carried out using the following Column DB 210 temp 1 = 60°C, time 1 = 5 min. rate 1 20°/min temp 2 = 200°C, time 2 = 5 min. The analysis is conducted on 1 pL of solution. The analysis is made quantitative by determining the response factors of the sulfide and internal standard in the usual manner. The dimethyldioxirane concentration is determined by measuring the sulfide concentration before and after adding the dioxirane. Under these conditions the following retention times are observed dodecane, 7.15 min sulfide, 8.2 min sulfoxide, 12.9 min. 

Dimethyldioxirane (52) and other methyldioxiranes are easily generated peroxides which have proved to be very useful oxygen atom transfer agents alkenes, sulfides and amines can all be oxidized and dimethyldioxirane is reduced to acetone. ... 

The formal addition of an oxygen atom across the carbonyl group gives rise to dioxiranes (equation 33). In practice, this reaction is effected with Oxone, and dimethyldioxirane (30) and other dioxiranes have been generated in solutions of their parent ketones.Dioxirane (30) has been implicated in oxidations of alkenes, sulfides and iinines. The formal addition of nitrogen across a carbon-oxygen double bond to afford oxaziridines has been reviewed (equation 34).There are also many methods available for the indirect conversion of carbonyl compounds to aziridines > and thiiranes using multi-step conversions. 

The oxidation of organic compounds with dioxirane reagents has emerged as an important synthetic method [93,94,95]. The effective use of dimethyldioxirane and methyl(trifluoromethyl)dioxirane for the mild and efficient oxidation of olefins, sulfides, amines, and saturated hydrocarbons naturally raised the question whether chiral versions of these reagents can be developed. 

FIGURE 3.1 Thermodynamic oxygen transfer potentials. DMDO, dimethyldioxirane Ac, CH3C(0) DMSO, dimethyl sulfoxide DMS, dimethyl sulfide. 

There was further study of indole-2,3-epoxides and indole-2,3-dioxetanes. Dioxetanes can be isolated from 1-acyl indoles by photo-oxygenation and are accompanied by more stable hydroperoxides. The oxetanes can be converted to indole-2,3-epoxides by deoxygenation with dimethyl sulfide. <94J0C2733, 94JCS(P2)1503> The epoxides can also be prepared by oxidation of 1-acyl-indoles by dimethyldioxirane. The indole-2,3-epoxides... 

Oxidation of Sulfur Functional Groups. Dimethyldioxirane rapidly oxidizes sulfides to sulfoxides and converts sulfoxides to sulfones (eq 25). The partial oxidation of sulfides to sulfoxides can be controlled by limiting the quantity of DDO. Since Oxone is one of the many reagents that can perform these reactions, the extra effort involved in preparing DDO solutions is often not warranted. An exception involves the transformation of thiophenes to the corresponding sulfones (eq 26). A similar procedure gives a-0x0 sulfones by DDO oxidation of thiol esters (eq 21)P... 

A further synthesis of hypothemycin (481) was published by the group of Winssinger in 2009 (384). They used a partial solid-phase strategy with a benzylic sulfide linker to build up the resorcylic macrolactone. The applied macrolacto-nization step proceeded extremely efficiently and epoxidation of LL-Zl640-2 (567) with dimethyldioxirane afforded hypothemycin with excellent regio- and stereoselectivity, but in a poor yield. 

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