1: tetrahydrofuran; diethyl ether / 2 h / -20 °C 2: 162 mg / Dess-Martin periodinane / CH2Cl2 / 3 h / 20 °C 3: 62.5 percent / urea-H2O2 complex; trifluoroacetic anhydride / CH2Cl2 / 48 h / 20 °C 4: 60 percent / H2; Raney nickel / methanol / 3 h / 20 °C 5: 36 percent / NaHCO3; ZnCO3 / CH2Cl2 / 20 h / 20 °C View Scheme