1: tetrahydrofuran / -100 - -78 °C 2: pyridinium p-toluenesulfonate / 1,2-dichloro-ethane / 2 h / Heating 3: 88 percent / sodium metaperiodate / methanol; H2O / Ambient temperature 4: 2M KOH / methanol / 0.17 h / Heating 5: 1.) HCO2H; 2.) O2 / 1.) MeOH, r.t., 2 h; 2.) CH2Cl2, r.t., 3 h View Scheme