Performic acid epoxidizing agent

In work reported elsewhere (31) we have shown that the oxidation of styrene under mild conditions is promoted by many group VIII metal complexes. The product profile depends on the nature of the metal center and often differs from that observed when radical initiators are used (Table IX). Substantial quantities of styrene oxide are found in some cases but not in others (31). The epoxide which is formed, however, seems to arise via the co-oxidation of styrene and formaldehyde which is formed by oxidative cleavage of the double bond. Formaldehyde may be oxidized to performic acid or formylperoxy radicals which are efficient epoxidizing agents. Reactions of styrene with oxygen in the presence of group VIII complexes exhibit induction periods and are severely retarded by radical inhibitors (31). Thus, the initial step in the oxidation of styrene in the presence of the Ir(I),Rh(I), Ru(II), and Os(II) com-... 

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. 

The benzofuran epoxides 70 are found to be the most reactive epoxides functioning as alkylative agents. Polyunsaturated free fatty acids, namely linoleic, arachidonic, and eicosatrienic acids, and also their methyl esters have been epoxidized using lb <2006HCA2243>. When the reaction is performed in water, it has been found that due to supramolecular organization of fatty acids into a micelle, the C=C bonds closest to the aqueous-micelle interface are most prone to epoxidation. 

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