Tantalum(V) or niobium(V) catalyzed oxidation of sulfides with 30% hydrogen peroxide

Bi2O3 catalyzed asymmetric oxidation of sulfides

“…[7][8][9][10][11] Owing to their biological activity, the enantioselective oxidation of sulfides is a well investigated area of organic synthesis. [12][13][14][15][16][17][18][19][20][21][22][23] For the first time, in mid-eighties Kagan et al have reported enantioselective oxidation of sulfides by using modified Sharpless oxidation. 24 Later, tremendous work has been done by Bolm et al in this area.…”

Niobium(V) Chloride Catalyzed Oxidation of Dithioacetals with 30% Hydrogen Peroxide: A Concise Preparation of Bissulfonylmethylene Compounds

“…As we noted in the introduction, we found that methanol is the good solvent for the synthesis of sulfones from the oxidation of sulfides with 30% hydrogen peroxide catalyzed by Nb(V), 10) Ta(V), 10,11) or NbC. 12) Therefore, the reactions of 2-methyl-2-(2-naphthyl)-1,3-dithiane (2a) with 16 eq of 30% hydrogen peroxide in methanol were examined in the presence of 0.1 eq of niobium or tantalum compounds ( Table 1).…”

“…The resulting hydroxides react with hydrogen peroxide or methyl hydroperoxides (derived from the reaction of hydrogen peroxide with methanol) to produce niobium(V) peroxides. Because the niobium(V) compounds act as a Lewis acid, 10,11) the methanol coordinates with the metal peroxides to produce niobium(V) peroxide complexes. These peroxide complexes oxidize dithioacetals and revert back to the niobium(V) hydroxides (or a complex with the solvent).…”

“…We have been working on the oxidations of organosulfur compounds using hydrogen peroxide as the oxidant, and reported that the reaction of sulfides with 30% hydrogen peroxide in the presence of catalytic amounts of Nb(V), 10) Ta(V), 10,11) or niobium carbide (NbC) 12) in methanol provided the corresponding sulfones in high yields (Chart 2).…”

Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide

“…The most widely used method for the preparation of sulfoxides and sulfones is the oxidation of the corresponding sulfide. For this reason, sulfide oxidation to sulfoxides and sulfones has been the subject of many studies, and several methods for this transformation have been reported in the literature [3][4][5][6][7][8]. Some traditional oxidizing reagents used for this purpose include nitric acid, trifluoroperacetic acid, hydrogen peroxide, nitromethane solution in dilute NO 3 H/H 2 SO 4 , iodic acid, other hypervalent iodine reagents, and CAN (cerium ammonium nitrate), among others [1,[8][9][10][11].…”