Sulfoxide complexes hydrogenation

Mercury chloride thioether complexes have been oxidized to the corresponding sulfoxide complexes by treatment with hydrogen peroxide (76) [Eq. (30)]... 

Although sulfoxide complexes have been studied as hydrogenation catalysts (vide infra), little work on the related hydroformylation reaction has been reported. A patent by B.P. (196) covers the use of... 

Electrochemically, the reduction of activated sulfoxides (unsaturated or aromatic) in protic media exhibits a specific step leading to corresponding sulfides. However, in acidic solutions of sulfoxides a hydrogen reduction wave can be seen [223, 224] because of the reduction of their pro-tonated form. On the contrary, in the absence of electrophiles (in aprotic DMF), the reduction of aromatic sulfoxides was reported to afford [225] a complex between the reduced form and the substrate (the process therefore would be analogous to... 

This chapter reports principally on studies with ruthenium chiral phosphine and chiral sulfoxide complexes and their use for catalytic hydrogenation. We have used the familiar diop ligand, [2R,3R-(—)-2,3-Oisopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino) butane] (7) a related chiral chelating sulfoxide ligand dios, the bis(methyl sulfinyl)butane analog (21) (S,R S,S)-(+)-2-meth-ylbutyl methyl sulfoxide(MBMSO), chiral in the alkyl group and R-(+)-methyl para-tolyl sulfoxide(MPTSO), chiral at sulfur. Preliminary data on some corresponding Rh(I) complexes are presented also. 

Ruthenium(II) complexes dimethyl sulfoxide, 490 hydrogen sulfide, 516... 

The sulfoxide complexes 138a-c were prepared by oxidation of the corresponding sulfides with hydrogen peroxide153. 

Copper(II) complex (5) catalyses the oxidation of sulfides to sulfoxides with hydrogen peroxide in high yields. Addition of a catalytic amount of TEMPO to the reaction mixture enhances the conversion and selectivity.181... 

Sulfoxides form hydrogen-bonded complexes with a-methoxyphenylacetic acid, which results in differential shielding of the two substituents. ... 

A Cr(VI) sulfoxide complex has been postulated after interaction of [CrOjtClj] with MejSO (385), but the complex was uncharacterized as it was excessively unstable. It was observed that hydrolysis of the product led to the formation of dimethyl sulfone. The action of hydrogen peroxide on mesityl ferrocencyl sulfide in basic media yields both mesityl ferrocenyl sulfoxide (21%) and the corresponding sulfone (62%) via a reaction similar to the Smiles rearrangement (165). Catalytic air oxidation of sulfoxides by rhodium and iridium complexes has been observed. Rhodium(III) and iridium(III) chlorides are catalyst percursors for this reaction, but ruthenium(III), osmium(III), and palladium(II) chlorides are not (273). The metal complex and sulfoxide are dissolved in hot propan-2-ol/water (9 1) and the solution purged with air to achieve oxidation. The metal is recovered as a noncrystalline, but still catalytically active, material after reaction (272). The most active precursor was [IrHClj(S-Me2SO)3], and it was observed that alkyl sulfoxides oxidize more readily than aryl sulfoxides, while thioethers are not oxidized as complex formation occurs. 

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