1: 8.6 g / NaI / acetone / Heating 2: 3α,20β-hydroxysteroid dehydrogenase, K2HPO4 / ethanol / 24 h / 25 °C / other enzymes, other substrates, KM, Vmax; stereoselectivity 3: 86 percent / Ph3P, DEAD / tetrahydrofuran 4: 95 percent / 20percent aq. K2CO3 / methanol / 2 h / Ambient temperature 5: 1) MeOH, 80 deg C, overnight, 2) ether View Scheme