Potassium hydrogen persulfate epoxidation with

Selective oxidation of either the aromatic ring or the side chain can also be accompHshed. For example, epoxidation of the double bond of cinnamic acid is effected in excellent yield by treatment with potassium hydrogen persulfate (10). 

The most widely used and, presumably, the most chemoselective reagents for the epoxidation of nucleophilic C—C double bonds are the peroxycarboxylic acids (see Houben-Weyl, Vol. IV/ 1 a, p 184, Vol. Vl/3, p 385, Vol. E13/2, p 1258). Using chloroform as solvent, epoxidation rates are particularly high79. Reactive or acid/base sensitive epoxides can often be obtained with dimethyldioxirane (see Houben-Weyl, Vol. R13/2, p 1256 and references 15, 16, 87-90), peracid imides (see Houben-Weyl, Vol. IV/1 a, p 205, Vol. VI/3, p 401, Vol. E13/2, p 1276) (prepared in situ from nitriles and hydrogen peroxide), hydroperoxy acetals (see Houben-Weyl, Vol. El3/2, p 1253) or peroxycarbonic acid derivatives (see Houben-Weyl, Vol. IV/la, p 209 and references 17-19) as oxidants. For less reactive alkenes, potassium hydrogen persulfate is a readily available reagent for direct epoxidation20. 

De Poorter, B. and B. Meunier (1985). Metalloporphyrin-catalyzed epoxidation of terminal olefins with hypochlorite salts or potassium hydrogen persulfate. Perkin Trans. U,J. Chem. Soc. 1735-1740. 

Oxidation of Sulfoxides. Dialkyl, alkyl aryl, and diaryl sulfoxides are readily oxidized to sulfones in excellent yields under mild conditions (—30 °C) in MeCN by the peroxy intermediate (1). Oxidation of the unsaturated sulfoxide (11) was chemose-lective it furnished the sulfone (12) in 70% yield when reacted with (1) for 5 h. The double bond was not epoxidized. Similar chemoselective epoxidation has been carried out with only one other reagent (potassium hydrogen persulfate). ... 

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