Tetrahydrofuran → 3alpha-Acetylthio-6-methyleneandrostan-17-one

Participants

Reaction Steps

To a stirred solution of 3α-acetylthioandrostane-6,17-dione (Prepn. 78, 600 mg) in THF (8 mL) cooled at −50° C., a solution of ylide prepared from methyltriphenylphosphonium bromide (1.47 g) in THF dry (8 mL) at −50° C. and potassium tert-butoxide (484 mg), was added. After 2 h the temperature was raised to room temperature. The mixture was quenched by addition of 5% NaH2PO4 aqueous solution and extracted with EtOAc (2×60 mL). The combined organic extracts were washed with 5% NaH2PO4 aqueous solution, brine, dried over Na2SO4, and evaporated to dryness. The residue was purified by flash chromatography (n-hexane/EtOAc 9/1) to give 3α-acetylthio-6-methyleneandrostan-17-one (210 mg, 35% yield) and 3α-mercapto-6-methyleneandrostan-17-one (208 mg, 35% yield). 1H-NMR (300 MHz, DMSO-d6, ppm from TMS): 3α-acetylthio-6-methyleneandrostane-17-one: δ 4.73 (1H, m), 4.39 (1H, m), 3.96 (1H, m), 2.44-0.84 (20H, m), 2.29 (3H, s), 0.75 (3H, s), 0.66 (3H, s); 3α-mercapto-6-methyleneandrostane-17-one: δ 4.73 (1H, m), 4.38 (1H, m), 3.57 (1H, m), 2.52 (1H, d), 2.45-0.95 (20H, m), 0.76 (3H, s), 0.63 (3H, s).

Provenance & Evidence