Oxidation of sulfide to sulfone

Sulfones. This oxidant is useful for selective oxidation of sulfides to sulfones (10,328). Oxidations of acid-sensitive substrates should be buffered with Na2C03. 

Oxidation of sulfides and sulfoxides using Oxone dispersed on silica gel or alumina was reported . A study of surface mediated reactivity of Oxone compared its reactivity with that of ferf-butyl hydroperoxide. Oxidation of sulfides to sulfones in aprotic solvents mediated by Oxone on wet montmorillonite or clay minerals proceeds in high yields. Interestingly, when Oxone on alumina is applied for selective oxidation of sulfides in aprotic solvents, the product distribution is temperature-dependent and sulfoxides or sulfones are obtained in good to excellent yields (equation 56) . ... 

THE FIRST EXAMPLE OF DIRECT OXIDATION OF SULFIDES TO SULFONES BY AN OSMATE-MOLECULAR OXYGEN SYSTEM... 

The oxidation of sulfides to sulfones has been the subject of extensive studies, since sulfones are useful synthons for the construction of various chemically and biologically significant moleculesJ Recently, a new catalytic system has been developed by exchanging potassium osmate onto chloride-saturated layered double hydroxides (Figure 9.1), which we have shown to be an efficient catalyst for the direct oxidation of sulfides to sulfones, using molecular oxygen as the stoichiometric oxidant and with delivery of two oxygen atoms simultaneously to the sulfide, reminiscent of olefin dihydroxylation reactions. 

Sulfunes. A recent preparation of thietane 1,1-dioxide1 emphasizes the advantage of tungstic acid catalysis2 in the hydrogen peroxide oxidation of sulfides to sulfones an induction period is eliminated and the yield improved. 

Oxidation of sulfides to sulfones.[ Sulfides are oxidized chemoselectively to sulfones by KHSOs (3 equivalents) in high yield. Peracids are usually used for this oxidation, but can also oxidize olefinic groups. Oxidation of sulfides to sulfoxides is also possible with 1 equivalent of reagent. 

A recent method for the highly chemoselective oxidation of sulfides to sulfones using Af-methylmorpholine IV-oxide (NMP) and a catalytic perruthenatc was found to be also applicable in the presence of isolated or allylic double bonds [115]. 

Gokel, G.W., Gerdes, H.M., and Dishong, D.M., Sulfur heterocycles. 3. Heterogenous, phase-transfer, and acid catalyzed potassium permanganate oxidation of sulfides to sulfones and a survey of their carbon-13 nuclear magnetic resonance spectra, J. Org. Chem., 45, 3634, 1980. 

Sodium percarbonate (PCS) can also be employed for the oxidation of sulfides to sulfones in acetonitrile assisted by ultrasound.415... 

Peroxyphthalic add, o-C,iH4(C02H)C03H, is obtained from phthalic anhydride and hydrogen peroxide [330] or sodium hydrogen peroxide [331] and is applied usually in ethereal solutions to epoxidations [330, 332], the Baeyer-Villiger reaction [333, 334], and oxidations of sulfides to sulfoxides [163, 335] and sulfones [336, 337]. The oxidation of sulfides to sulfones takes precedence over epoxidation, as evidenced by the fact that unsaturated ketone thioacetals are oxidized to unsaturated disulfones [337]. 

Oxidation. lodosobenzene has been suggested as a reagent for the oxidation of sulfides to sulfones. Thus a solution of 12 g. of the thiodiglycol (1) in 50 ml. of water was heated on the steam bath with 1.15 equivalents of lodosobenzene for about 15 min., cooled, and filtered. After removal of the iodobenzene layer, the solution was... 

Based on the facile oxidation of sulfides to sulfones with Oxone, phenyl vinyl sulfone (a multipurpose synthetic reagent) can be obtained in three steps from 2-bromoethanol, that is, displacement with PhSH, oxidation, and dehydration (via mesylation). ... 

T. Lee et. al. [167] reported a series of 2,5,6,7-tetrasubstituted thiazolo[4,5-b]pyridine derivatives (168) from solid-phase s)mthesis. Thorpe-Ziegler type cyclization of solid supported cyanocarbonimidodithioate with a-halo ketones gave thiazole resin, which were transformed to the preferred thiazolop5rridine resin by the Friedlander procedure under microwave irradiation conditions. After oxidation of sulfides to sulfones, nucleophilic desulfonative substitution with amines 4elded the target thiazolo[4,5-b]pyridine derivatives. 

Bearing these considerations in mind, Reddy and Verkade prepared a titanium alkoxide complex, 72, with good stability toward moisture for the selective oxidation of sulfides to sulfones and sulfoxides with hydrogen peroxide in recyclable ionic liquid solvents at room temperature [56]. They optimized reaction conditions and recovering procedure for thioanisole 71, and used their obtained results for oxidation of different aliphatic, aromatic and xmsaturated sulfides. Their results proved the chemoselectivity... 

The Ni(II) complex of the perfluorinated )8-diketone, C7F15COCHCOC7F15 actively catalyzed the oxidation of a variety of aldehydes to the corresponding carboxylic acids (248) with high jdeld vmder mild conditions (Scheme 49). The solvent used was made of perfluorodecalin and toluene, and the catalyst was recycled several times in the fluorous phase vsrith only a negligible loss of activity. The same catalyst/solvent system was also used for the oxidation of sulfides to sulfones and sulfoxides (Scheme 49). Addition of 2-methylpropanal to this reaction system led to the in situ generation of a peracid, which resulted in high product yields. 

A small library of alkyl, sulfone, and carboxamide-functionalized pyrazoles and isoxazoles has been developed via a rapid sequential condensation of various R-acylketene dithioacetals with hydrazine hydrate or hydroxylamine hydrochloride, followed by oxidation of sulfide to sulfone using water as the reaction medium [3] (Scheme 8.3). An efficient and safe oxidation of sulfides to the corresponding sul-fones using sodium per borate system in aqueous medium has also been reported. The concise and two-step synthesis of trisubstituted pyrazoles and isoxazoles was investigated under a variety of reaction conditions. The newly developed methodology has the advantage of excellent yield and chemical purity with short reaction time using water as a solvent. 

Oxone, which is commercially available as a 2 1 1 mixture of KHSO5, KHSO4, and K2SO4, has been used for the oxidation of sulfides to sulfoxides [15]. It shows a tendency to overoxidation, and was originally used for the oxidation of sulfides to sulfones [16]. More recently, some improvements were obtained with surface-mediated oxone oxidations, the oxone being bound to a silica gel surface (Eq. (8.3)). However, some sulfone was still formed. 

A new, facile procedure for the oxidation of sulfides to sulfones, employing catalytic OSO4 and tertiary amine iV-oxides, has been applied to various thiosugars. The chemoselectivity of the method was demonstrated by the high yielding transformation of the unsaturated sulfide... 

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