Peracetic acid epoxidizing agent

In the procedures to date, the most frequent epoxidizing agent has been perbenzoic acid bearing an electron-attracting substituent. The use of p-methoxy-carbonylperbenzoic acid prepared by photooxidative means has been reported. In industrial syntheses, in situ performic acid, peracetic acid, and perpropionic acid °have been utilized in a two-phase solvent. 

Following the catalytic mechanism reported in Scheme 16.8, we demonstrated the role of peracetic acid, generated in situ, in promoting the formation of PINO by undergoing molecule-induced homolysis with NHPI (path a), while the acyl peroxyl radical resulted to be the effective epoxidizing agent (path b). 

By epoxidation of unsaturated organosilicon compounds by perbenzoic, perphthalic, 40% peracetic acid [4] and peroxytrifluoroacetic acid [4] was shown, that the best epoxidation agent is peroxytrifluoroacetic acid. During epoxidation of 1.1.3.3-tetramethyldivinyldisiloxane and 1.1.3.3.5.5.7.7-octaphenyl-1.7-divinyltetrasiloxane by perbenzoic acid corresponding diepoxyderivatives has been obtained with 60-65% yield. 

The most widely accepted method for epoxidation of alkenes remains oxidation with organic peracids. The early work (up to 1970) in this field shows that a large number of dienes and polyenes were oxidized in this manner . The most commonly used peracids are peracetic, monoperphthalic and perbenzoic acids which are most dominant in industrial applications. On the other hand, in laboratory procedures m-chloroperbenzoic acid, MCPBA, is often used, with trifluoroperacetic acid cited in more difficult transformations. Recently, the transportation of m-chloroperbenzoic acid has been restricted and the use of other peroxygen agents has been gaining acceptance as a general alternative. Among the substrate types epoxidized it would be especially worthy to point out polyunsaturated... 

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