m-Chloroperbenzoic acid → (2alpha-3alpha,5alpha)-2,3-Epoxypregnan-20-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-α-pregn-2-en-20-ol (12) (660 mg, 2.18 mmol) in anhydrous dichloromethane (20 mL) at 0° C. under an atmosphere of argon was added in six portions m-CPBA (733 mg, 3.27 mmol). The solution was stirred over a period of 1 h at 0° C. and then allowed to return to room temperature overnight. The resulting solution was diluted with dichloromethane (30 mL) and successively washed with a Na2S2O3 aqueous solution (10%) and a Na2CO3 aqueous solution (10%), dried with MgSO4, filtered and evaporated to dryness. Purification by FCC (EtOAc/hexanes, 5:95) yielded 511 mg (73%) of title compound 13 as a white solid. 1H NMR (acetone-d6) δ: 0.74 (s, 18-CH3), 0.79 (s, 19-CH3), 1.07 (d, J=6.1 Hz, 21-CH3), 0.60-2.30 (residual CH and CH2), 3.06 (m, 2×CH of epoxide), 3.62 (m, 20-CH); 13C NMR (CDCl3) δ: 12.4, 12.9, 20.7, 23.6, 24.4, 25.6, 28.4, 29.0, 31.7, 33.6, 35.4, 36.2, 38.2, 39.9, 42.3, 51.1, 52.4, 53.7, 55.7, 58.5, 70.6, LRMS for C21H34O2 [M+H]+: 319.1 m/z.

Provenance & Evidence