Sulfoxides methyltrioxorhenium

Oxidation of thiophene with Fenton-like reagents produces 2-hydroxythiophene of which the 2(570 One isomer is the most stable (Eq. 1) <96JCR(S)242>. In contrast, methyltrioxorhenium (Vn) catalyzed hydrogen peroxide oxidation of thiophene and its derivatives forms first the sulfoxide and ultimately the sulfone derivatives <96107211>. Anodic oxidation of aminated dibenzothiophene produces stable radical cation salts <96BSF597>. Reduction of dihalothiophene at carbon cathodes produces the first example of an electrochemical halogen dance reaction (Eq. 2) <96JOC8074>. 

Methyltrioxorhenium 41 has been established as a good catalyst for the selective oxidation of sulfides to sulfoxides by H2O2319 320. Both mono 42 and diperoxo species 1 (equation 30) are reactive in this oxidation. High selectivity of sulfoxide over sulfone has been reported, except in the presence of large contents of water in the reaction mixture319. 

Sulfoxidation is catalyzed by a Fe(III)-corrolazine, and surprisingly the active oxidant is a ferric hydroperoxide species. Complete oxidation of thiols to sulfoiuc acids occurs on treatment with H2O2 and methyltrioxorhenium in MeCN at room temperature. ... 

Methyltrioxorhenium(VII) (MeReOs) is an excellent catalyst for the oxidation of sulfides to sulfoxides. ... 

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