Induced reactions involving other peroxy compounds

2 Induced reactions involving other peroxy compounds 

Induced decomposition of hydrogen peroxide can be interpreted as follows. The HO2 radical formed in reaction (91) reduces OSO4, which will be re-oxidised 

EFFECT OF CHANGES IN THE CONCENTRATION OF OSMIC ACID ON THE INDUCED REACTION BETWEEN H2O2, OSO4. AND KM11O4 Data of Csinyi et 

The OH radical formed in reaction (97) forms a HO2 radical again in reaction (85) thus, without any extra oxidizing agent being present, a considerable amount of hydrogen peroxide is decomposed. 

Dependence of the value of Fj on the titrating rate, on the dilution and on the concentration of the reactants can be interpreted in a similar way as for the H2O2-H2S2O8 system. 

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Allylic alcohols can be converted to epoxy-alcohols with tert-butylhydroperoxide on molecular sieves, or with peroxy acids. Epoxidation of allylic alcohols can also be done with high enantioselectivity. In the Sharpless asymmetric epoxidation,allylic alcohols are converted to optically active epoxides in better than 90% ee, by treatment with r-BuOOH, titanium tetraisopropoxide and optically active diethyl tartrate. The Ti(OCHMe2)4 and diethyl tartrate can be present in catalytic amounts (15-lOmol %) if molecular sieves are present. Polymer-supported catalysts have also been reported. Since both (-t-) and ( —) diethyl tartrate are readily available, and the reaction is stereospecific, either enantiomer of the product can be prepared. The method has been successful for a wide range of primary allylic alcohols, where the double bond is mono-, di-, tri-, and tetrasubstituted. This procedure, in which an optically active catalyst is used to induce asymmetry, has proved to be one of the most important methods of asymmetric synthesis, and has been used to prepare a large number of optically active natural products and other compounds. The mechanism of the Sharpless epoxidation is believed to involve attack on the substrate by a compound formed from the titanium alkoxide and the diethyl tartrate to produce a complex that also contains the substrate and the r-BuOOH. ... 

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