1: 1.) NaIO4, 2.) NaBH4 / 1.) THF, H2O, room temperature, 2 h, 2.) MeOH, room temperature, 30 min 2: 69 percent / pyridine / 12 h / 0 °C 3: 70 percent / iPr2NEt / CH2Cl2 / 1 h / Ambient temperature View Scheme

sodium tetrahydroborate; sodium periodate 1.) THF, H2O, room temperature, 2 h, 2.) MeOH, room temperature, 30 min; Yield given. Multistep reaction;

1: 1.) NaIO4, 2.) NaBH4 / 1.) THF, H2O, room temperature, 2 h, 2.) MeOH, room temperature, 30 min 2: 69 percent / pyridine / 12 h / 0 °C View Scheme