1: 92 percent / pyridine / dimethylformamide / 20 h / 20 °C 2: 100 percent / NaBH4 / tetrahydrofuran; H2O / 2 h / 20 °C 3: 90 percent / pyridine / dimethylformamide / 15 h / 24 °C 4: 92 percent / SnCl2 / CH2Cl2 / 0.5 h / 20 °C 5: 73 percent / Dess-Martin periodinane / CH2Cl2 / 10 h / 20 °C 6: TBAF / tetrahydrofuran / 2 h / 0 °C View Scheme

sodium periodate; sodium hydrogencarbonate T=10 - 15°C; 6 h;