Selenoxides as Catalysts for Epoxidation and Baeyer-Villiger Oxidation with Hydrogen Peroxide

Aryl benzyl selenoxides are catalysts for the epoxidation of various olefinic substrates and the Baeyer-Villiger oxidation of aldehydes and ketones with H2O2 in CH2Cl2 at 2.5 mol% catalyst. Benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide (4) was the most effective catalyst while 2-(dimethylamino)phenyl benzyl selen­oxide was the least. Mono-, di-, and trisubstituted alkenes were ­epoxidized and adamantanone, cyclohexanone, and 3,4,5-trimethoxybenzaldehyde underwent BaeyerVilliger oxidation using 4 and H2O2. Competition studies showed that epoxidation reactions were faster than Baeyer-Villiger oxidations although the selectivity varied only from 1.3:1 to 4.6:1.