1: triethylsilane; trifluoroacetic acid / acetonitrile / 12 h / 0 - 20 °C 2: water; sodium periodate; osmium(VIII) oxide / tetrahydrofuran; tert-butyl alcohol / 1 h / 0 °C 3: boron trifluoride diethyl etherate; triethylsilane / dichloromethane / 2.5 h / -78 °C View Scheme