Epoxides from Olefins and Peroxidic Reagents

The most widely used reaction in this category is the conversion of olefins to epoxides. In most cases, one of several peroxycarboxylic acids is used to effect oxidation. m-Chloroperoxybenzoic acid, which is commercially available or readily prepared and is a quite stable solid, is the most popular reagent. Peroxyacetic acid, peroxybenzoic acid, peroxytrifluoroacetic acid, and others, however, have also been used frequently. 

It has been demonstrated that ionic intermediates are not involved in the epoxidation process. The reaction rates are not directly related to solvent polarity. Syn addition with retention of the stereochemistry of the olefin substituents is consistently observed. The reaction is therefore generally believed to be a concerted process. The most satisfactory representation of the transition state for the reaction is illustrated below  

A process that is effective for epoxidation and that completely avoids acidic 

Organic Peroxides, Vol. II, Wiley-Interscience, New York, NY, 1971, pp. 355-533. 

The stereochemistry of epoxidation with peroxycarboxylic acids has been well studied. Attack and addition of oxygen occurs preferentially from the less hindered side of the molecule. Norbornene, for example, gives a 96 4 exo endo ratio. Other examples where this general trend is followed are summarized in a review by 

Organic Peroxides, Vol. II, Wiley-Interscience, New York (1971), pp. 355-533 B. Plesnicar, in Oxidation in Organic Chemistry, Part C, W. Trahanovsky (ed.). Academic Press, New York (1978), pp. 211-253. 

SECTION 10.2. ADDITION OF OXYGEN AT CARBON-CARBON DOUBLE BONDS 

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The reagent is prepared from succinic anhydride and aqueous hydrogen peroxide and is used for the epoxidation of olefins, A satisfactory solvent is dimethylformamide containing a little water water is required for hydrolysis of the peroxide. 

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