mCPBA (1.17 g) was added to a stirred solution of 17β-hydroxy-4,4-dimethylandrost-5-en-3-one (1.00 g) in DCM (30 ml). After 8 h at RT, a 10% Na2SO3 aqueous solution was added. The mixture was neutralized by addition of 5% aqueous NaHCO3 solution and was extracted with DCM (3×100 ml). The combined organic extracts were washed with H2O, dried over Na2SO4, and evaporated to dryness. The mixture was purified by flash chromatography (SiO2, n-hexane/EtOAc 70/30) to give 5α,6α-epoxy-4,4-dimethyl-17β-hydroxyandrostan-3-one (230 mg, 23%).
