Sulfides sodium periodate

Keywords sulfide, sodium periodate, wet silica, microwave irradiation, sulfoxide... 

A second method uses sodium periodate (NaI04) as the oxidant in the presence of the readily available protein bovine serum albumin. In this procedure, the sulfide is complexed in the chiral envirorunent of the protein. Although the oxidant is achiral, it encounters the sulfide in a chiral envirorunent in which the two faces of the sulfide are differentiated. 

Oxidation of Sulfides to Sulfoxides and Sulfones - Sodium Periodate-Silica... 

The oxidation of sulfides to the corresponding sulfoxides and sulfones proceeds under rather strenuous conditions requiring strong oxidants such as nitric acid, hydrogen peroxide, chromic acid, peracids, and periodate. Using MW irradiation, this oxidation is achievable under solvent-free conditions and with desired selectivity to either sulfoxides or sulfones using 10% sodium periodate on silica (Scheme 6.34)... 

Rj = PhCH2 R2 = Ph Rj = Ph, n-C12ttz R2 = Me Scheme 6.34 Oxidation of sulfides to sulfoxides and sulfones by silica-supported sodium periodate. 

Reduction of the furan (152) with sodium borohydride gave diol 154 and its cyclization (P2SJ/CS2) formed 19% of sulfide (155). Periodate oxidation of 155 gave (92%) the corresponding sulfoxide (156). The latter reacted with dimethyl acetylenedicarboxylate forming the adduct 157 (70%) the formation of 157 is evidence of the presence of the thieno[3,4-c]furan system (158) as an intermediate. Cyclization of diketone 153 in the presence of phosphorus pentasulfide proceeds M. P. Cava and M. A. Sprecker, J. Amer. Chem. Soc. 94, 6214 (1972). 

Oxidation of the heterocycles with common reagents such as MCPBA, sodium periodate or hydrogen peroxide cleanly affords the sulfoxides and sulfones, and it is clear that the sulfur atom is the principal centre of reaction for electrophiles. While the sulfone is a quite inert functionality, the sulfoxides may be reduced to the sulfides with phosphorus pen-tasulfide as for the tetrahydro systems (78CJC1423). Positive halogen sources likewise react at sulfur, and the intermediate sulfonium halide rearranges, usually by 1,2-shift to the a-halo product. 

The present procedure is a specific example of the method generalized by Leonard and Johnson.8 The method employs extremely mild reaction conditions and affords high yields of sulfoxides (Note 9) free of contamination by sulfides or sulfones. Sodium periodate is easily and safely handled however, the higher cost of this reagent in comparison to certain other oxidants, e.g., hydrogen peroxide, may prohibit its use in large-scale reactions. 

On the pages which follow, general methods are illustrated for the synthesis of a wide variety of classes of organic compounds including acyl isocyanates (from amides and oxalyl chloride p. 16), epoxides (from reductive coupling of aromatic aldehydes by hexamethylphosphorous triamide p. 31), a-fluoro acids (from 1-alkenes p. 37), 0-lactams (from olefins and chlorosulfonyl isocyanate p. 51), 1 y3,5-triketones (from dianions of 1,3-diketones and esters p. 57), sulfinate esters (from disulfides, alcohols, and lead tetraacetate p. 62), carboxylic acids (from carbonylation of alcohols or olefins via carbonium-ion intermediates p. 72), sulfoxides (from sulfides and sodium periodate p. 78), carbazoles... 

The sulfide 1 (0.75 mmol) is dissolved in dichloromethane (2-3 mL) and adsorbed over silica supported sodium periodate (20%, 1.36 g, 1.28 mmol) that is wetted with 0.3 mL of water by thoroughly mixing on a vortex mixture. The adsorbed powdered material is transferred to a glass test tube and is inserted in an alumina bath (alumina 100 g, mesh 65-325, Fisher scientific bath 5.7 cm diameter) inside the microwave oven. The compound is irradiated for the time specified in the table and the completion of the reaction is monitored by TLC examination. After completion of the reaction, the product is extracted into ethyl acetate (2x15 mL). The removal of solvent at reduced pressure affords crude sulfoxide 2 that contains less than 5% sulfone. The final purification is achieved by column chromatography over silica gel column or a simple crystallization. 

Selective oxidation of sulfides to sulfoxides and sulfones was achieved over sodium periodate (NaI04) on silica (20%), under solvent-free conditions to afford either sulfoxides or sulfones as desired (Scheme 5) [49]. 

Scheme 6 Solvent-free oxidation of sulfides using sodium periodate-silica [49]...

The next step was to introduce the alkyl chain—this was best done by first oxidizing the sulfide to a sulfoxide, using sodium periodate. The sulfoxide was then deprotonated with -BuLi and alkylated with an alkyl iodide containing a carboxylic acid protected as its r-butyl ester. Reduction of the sulfoxide and hydrolysis back to the free acid gave biotin. 

Next, the protecting group was removed with acid, and the sulfide was oxidized to the sulfoxide with sodium periodate (NaI04) ready for elimination. Heating to 110°C then gave the Queen Bee Substance in 86% yield. 

Sodium periodate (sodium metaperiodate), NaI04 (mp 300 °C dec), which is commercially available, is applied mainly in aqueous or aqueous-alcoholic solutions. Like the free periodic acid, sodium periodate cleaves vicinal diols to carbonyl compounds [762], This reaction is especially useful in connection with potassium permanganate [763, 764] or osmium tetroxide [765], Such mixed oxidants oxidize alkenes to carbonyl compounds or carboxylic acids, evidently by way of vicinal diols as intermediates. Sulfides are transformed by sodium periodate into sulfoxides [322, 323, 766, 767, 768, 769, 770, 771, 772], and selenides are converted into selenoxides [773]. Sodium periodate is also a reoxidant of lower valency ruthenium in oxidations with ruthenium tetroxide [567, 774],... 

Sulfides containing sulfur in the ring are oxidized to cyclic sulfoxides. Ethylene sulfide, upon treatment with sodium periodate in aqueous methanol at 20-25 °C, is converted into ethylene sulfoxide in 65% yield [768]. With peroxybenzoic addin dichloromethane, a 77% yield is obtained [309] (equation 558). 

We shall be using [2,3] sigmatropic shifts in the reactions of allylic alcohols so this section is an introduction to that as well as describing perhaps the most tightly controlled method for making allylic alcohols. Allylic sulfides 40 are easily oxidised chemoselectively with reagents such as sodium periodate to the corresponding sulfoxides 41. More powerful oxidants tend to form the sulfone 42. 

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