dimethyl sulfoxide; trifluoroacetic anhydride in dichloromethane T=-78°C; 0.5 h;

1: 39 percent / SeO2 / dioxane; H2O / 24 h / Heating 2: 97 percent / pyridinium tosylate / CH2Cl2 / 24 h / Ambient temperature 3: 99 percent / 10percent aq. NaOH / methanol / 0.67 h / Ambient temperature 4: 76 percent / triethylamine / CH2Cl2 / 24 h / Ambient temperature 5: 76 percent / pyridinium tosylate / aq. ethanol / 24 h / 50 °C 6: 77 percent / Me2SO, trifluoroacetic anhydride / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 76 percent / triethylamine / CH2Cl2 / 24 h / Ambient temperature 2: 76 percent / pyridinium tosylate / aq. ethanol / 24 h / 50 °C 3: 77 percent / Me2SO, trifluoroacetic anhydride / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 18 percent / diisobutylaluminum hydride (DIBAH) / tetrahydrofuran; hexane / 4 h / -78 °C 2: 97 percent / pyridinium tosylate / CH2Cl2 / 24 h / Ambient temperature 3: 99 percent / 10percent aq. NaOH / methanol / 0.67 h / Ambient temperature 4: 76 percent / triethylamine / CH2Cl2 / 24 h / Ambient temperature 5: 76 percent / pyridinium tosylate / aq. ethanol / 24 h / 50 °C 6: 77 percent / Me2SO, trifluoroacetic anhydride / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 97 percent / pyridinium tosylate / CH2Cl2 / 24 h / Ambient temperature 2: 99 percent / 10percent aq. NaOH / methanol / 0.67 h / Ambient temperature 3: 76 percent / triethylamine / CH2Cl2 / 24 h / Ambient temperature 4: 76 percent / pyridinium tosylate / aq. ethanol / 24 h / 50 °C 5: 77 percent / Me2SO, trifluoroacetic anhydride / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 33 percent / aq. NaHCO3, silver trifluoroacetate / tetrahydrofuran / 48 h / Ambient temperature 2: 97 percent / pyridinium tosylate / CH2Cl2 / 24 h / Ambient temperature 3: 99 percent / 10percent aq. NaOH / methanol / 0.67 h / Ambient temperature 4: 76 percent / triethylamine / CH2Cl2 / 24 h / Ambient temperature 5: 76 percent / pyridinium tosylate / aq. ethanol / 24 h / 50 °C 6: 77 percent / Me2SO, trifluoroacetic anhydride / CH2Cl2 / 0.5 h / -78 °C View Scheme