Oxidation dimethyldioxirane

Direct oxidation of aromatics with m-CPBA in a two-phase system affords the most stable so-called K-region arene oxides in moderate yields.805 Careful control of pH is necessary to avoid acid-catalyzed rearrangement of the acid-sensitive product epoxides. The new powerful oxidants, dimethyldioxiranes,81,82 have also been used to convert arenes to arene oxides.806... 

Lithium aluminum hydride-Ceri-um(III) chloride, 159 Phosphine oxides Dimethyldioxirane, 120 Piperidines (see Heterocycles)... 

Murray and coworkers extended their studies of the novel oxidant dimethyldioxirane (19) to the reaction of quadricyclane (18 equation 7). The epoxide (15) was the nearly exclusive monooxidation product when the acetone solution of the oxidant was carefully dried, but in the presence of water a considerable amount of (17) was formed. 

Epoxidation of allylic phosphonates is achieved wilh success at room temperature witli MeCOjH in Et O, CF3CO3H in CHCI3, MCPBA in ( HT I- or MOO5/HMPA complex in CH2CI2 to give the corresponding 2,3-epoxyalkylphosphonates as a mixture of diastereomers. s- Allylic phosphonates may also be converted into 2,3-epoxyphosphonates via the 1,1,1-trifluorodimethyl-dioxirane-mediated oxidation. Dimethyldioxirane (DMD) in acetone at room temperature or methyl(trifluoromethyl)dioxirane (TED) in CHjClj at low temperature can be used instead of MCPBA. Because the reaction is quantitative, evaporation of acetone and excess of DMD allow the direct isolation of the pure product. 2,i55... 

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. 

This ether, developed for the protection of a pyranoside anomeric hydroxyl, is prepared via a Konigs-Knorr reaction from the glycosyl bromide and 2-(ben-zylthio)ethanol in the presence of DIPEA. It is cleaved, after oxidation with dimethyldioxirane, by treatment with LDA or MeONa. ... 

Dimethyldioxirane, acetone, CH2CI2, 0°, 24 h, > 95% yield. Ethers are also oxidized under these conditions. 

A modern reagent, that has found increased application, is dimethyldioxirane it is prepared in situ by oxidation of acetone with potassium peroxomonosul-fate KHSOs. ... 

Dimethyldioxirane oxidation of nitronaies anions affords the correspondmg carbonyl products. Highest yields are obtained when one equivalent of water Is added before the oxidation fEq. 6.9). ... 

The most widely employed methods for the synthesis of nitrones are the condensation of carbonyl compounds with A-hydroxylamines5 and the oxidation of A+V-di substituted hydroxylamines.5 9 Practical and reliable methods for the oxidation of more easily available secondary amines have become available only recently.10 11 12 13. These include reactions with stoichiometric oxidants not readily available, such as dimethyldioxirane10 or A-phenylsulfonyl-C-phenyloxaziridine,11 and oxidations with hydrogen peroxide catalyzed by Na2W044 12 or Se02.13 All these methods suffer from limitations in scope and substrate tolerance. For example, oxidations with dimethyldioxirane seem to be limited to arylmethanamines and the above mentioned catalytic oxidations have been reported (and we have experienced as well) to give... 

Secondary amines (R2NH) are oxidized to hydroxylamines (R2NHOH), which are resistant to further oxidation, by dimethyldioxirane and by benzoyl peroxide and NajHPOa. " ... 

Aliphatic and aromatic primary amines are rapidly and efficiently oxidized to nitro compounds by dimethyldioxirane.111 Dimethyldioxirane is prepared by reaction of OXONE (DuPont trademark)-2KHS05-KHS04-K2S04 with buffered aqueous acetone.112... 

In a typical reaction, w-butylamine (0.052 g, 0.7 mmol) in 5 ml of acetone is treated with 95 ml of dimethyldioxirane in acetone solution (0.05 M). The solution is kept at room temperature for 30 min with the exclusion of light (Eq. 2.53). Aromatic amines are converted into nitro compounds by oxidation using OXONE itself.113... 

The standard reaction sequence for transformation of a carboxylic acid into a nitro group is lengthy. Eaton has shortened this conversion via oxidation of isocyanates to nitro compounds with dimethyldioxirane in wet acetone (Eq. 2.71).140... 

Furan can be used as a source for malealdehyde. McKervey and coworkers found that oxidation of furan with dimethyldioxirane results in malealdehyde, which can be trapped in situ with a variety of Wittig reagents to generate dienes and polyenes (equation 174)295. The same sequence with substituted furans gives ketodienealdehydes and ketodieneesters295. 

The synthesis, X-ray structure and solid state NMR of 4,4-dimethyl-l,2-ditellurolane 75 have been reported <98PS(136-8)291>. Chemoselective oxidation of 1,2-dithiole derivatives using dimethyldioxirane to give products such as 76 has been described <00SUL169>. Cycloaddition of dihydroquinoline-fused l,2-dithiole-3-thiones 77 with DMAD gives the spiro 1,3-dithioles 78 <99CHE587>. Dicationic thiatelluroles such as 79 have been prepared <00AG(E)1318>, anti cancer properties have been claimed for the simple dithiolopyrrolones... 

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