1: 55 percent / SeO2 / CH2Cl2 / 1.5 h / Ambient temperature 2: 72 percent / t-butyl hydroperoxide, (-)-diethyltartarate / CH2Cl2 / -23 deg C, 30 min, RT., 1 h 3: 60 percent / pyridine / 15 h / 5 °C 4: 88 percent / NaI / acetone / 3 h / Heating 5: 37 percent / NaBH3CN / tetrahydrofuran; hexamethylphosphoric acid triamide / 3 h / 60 °C 6: 96 percent / aq. H2SO4 / tetrahydrofuran / 2 h / Ambient temperature View Scheme

in ethanol; water T=29°C; 40 h; Aspergillus niger, phosphate buffer, pH 6; Yield given. Yields of byproduct given. Title compound not separated from byproducts;