A NEW ROUTE TO EPOXIDES AND KETONES BY META-CHLOROPERBENZOIC ACID OXIDATION OF BETA-HYDROXYALKYL PHENYL SELENIDES AND TELLURIDES

Treatment of primary (β-hydroxy)alkyl phenyl selenides [R1R2C(OH)CH2SePh] with m- chloroperbenzoic acid (3-5 mol equiv.) in tetrahydrofuran or methanol gives the corresponding epoxides in high yield, cis-1-Methylene-4-t-butylcyclohexane oxide is obtained stereospecifically from 4-t-butyl-1-(phenylselenomethyl)cyclohexanol prepared by the addition of α-(phenylseleno)-methyl anion to 4-t-butylcyclohexanone. On the other hand, similar oxidation of secondary (β-hydroxy)alkyl phenyl selenides [R1R2C(SePh)CH2OH] affords the unexpected carboxylic acids or their esters. When a phenyl group is present on the carbon bearing the OH moiety in β-hydroxy selenides and tellurides [i.e.. PhRC(OH)CH2MPh; M = Se, Te; R = alkyl], the oxidation is accompanied by phenyl migration to afford ketones. The reaction can be applied to one-carbon-homologated ring expansion of the benzene-ring-fused cyclic ketones by combining with the addition of an α- (phenylseleno)methyl or α-(phenyltelluro)methyl moiety to the ketones.