Peroxide oxidation of Δ4-3-ketosteroids

Article abstract of DOI:10.1139/v82-268

Treatment of Δ⁴-3-ketosteroids with tert-butyl hydroperoxide in the presence of lithium hydroxide leads to the formation of the corresponding 4β,5β epoxides stereospecifically and in good yield.The stereospecificity of this reaction is explicable in terms of the accepted mechanism for the hydrogen peroxide epoxidation of Δ⁴-3-ketosteroids.The use of aqueous sodium peroxide as oxidant leads to the production of the corresponding Δ⁴-3,6-diones.A mechanism for this reaction is proposed in which the key step is autooxidation of the corresponding deconjugated Δ⁵-3-ketone, produced from the starting material in situ by the action of the reagents.Lithium peroxide does not oxidize androst-4-ene-3,17-dione at C-6, but produces the 4,5-epoxides in low yield together with an A-nor-3,5-secoacid.