To a solution of triphenylphosphine (2.38 g) in THF (140 mL) cooled at 0° C., diisopropyl azodicarboxylate (1.79 mL) was added dropwise. After stirring for 30 minutes, thioacetic acid (0.65 mL) and androstane-3β,6α,17β-triol (2.00 g) were added. After 2 hrs at 0° C. and overnight at room temperature EtOAc was added. The mixture was washed with water and the organic layer evaporated to dryness. The crude product was purified by flash chromatography (SiO2, cyclohexane:EtOAc 55:45) to give 3α-acetylthioandrostane-6α,17β-diol (1.60 g, 66%). 1H-NMR (300 MHz, DMSO-d6, ppm from TMS): δ 4.42 (1H, bb), 4.28 (1H, bb), 3.91 (1H, bb), 3.42 (1H, m), 3.11 (1H, m), 2.28 (3H, s), 2.00-0.80 (20H, m), 0.74 (3H, s), 0.60 (3H, s).
