1: NaBH4 / ethanol; H2O / Ambient temperature 2: 0.4N HCl / 1.) 95 deg C, 90 min; 2.) RT, 30 min 3: pyridine / 20 h / 20 °C View Scheme

1: NaBH4 / ethanol; H2O / Ambient temperature 2: 0.4N HCl / 1.) 95 deg C, 90 min; 2.) RT, 30 min 3: pyridine / 20 h / 20 °C 4: 65 percent / CF3SO2OSiMe3, hexamethyldisilazane / CH2Cl2 / 20 h / Ambient temperature 5: 97 percent / CH3ONa / methanol / Ambient temperature View Scheme