1: Ac2O / CH2Cl2 / 3.5 h / Heating 2: 1) Bu2SnO / 1) benzene, reflux, 24 h, 2) toluene, a) -40 deg C, 2 h, b) to r.t. 3: 1) Et3N, 2,4,6-trichlorobenzoyl chloride, 2) 4-(dimethylamino)pyridine / 1) THF, r.t., 3.5 h, 2) THF, toluene, reflux, 10 min 4: 86 percent / Ph3C*BF4 / CH2Cl2 / 48 h / Heating View Scheme

With  acetic anhydride in  dichloromethane 3.5 h;  Heating;   

With  sodium hydroxide; sodium ruthenate 0.5 h;  Ambient temperature;   

Multi-step reaction with 4 steps 1: 1) BH3*THF, 2) 3 M NaOH, 30percent H2O2 / 1) THF, 0 deg C, 20 h, 2) THF, r.t., 3 h2: 1) (COCl)2, DMSO, 2) Et3N / 1) CH2Cl2, -78 deg C, 2 min, 2) CH2Cl2, -78 deg C, 1 h3: 1 M KMnO4 / 2-methyl-propan-2-ol / 0.08 h / pH 7 phosphate buffer4: 86 percent / 1 M NaOH, Na2RuO4 / 0.5 h / Ambient temperature  

Multi-step reaction with 3 steps 1: Ac2O / CH2Cl2 / 3.5 h / Heating2: 1) Bu2SnO / 1) benzene, reflux, 24 h, 2) toluene, a) -40 deg C, 2 h, b) to r.t.3: 1) Et3N, 2,4,6-trichlorobenzoyl chloride, 2) 4-(dimethylamino)pyridine / 1) THF, r.t., 3.5 h, 2) THF, toluene, reflux, 10 min  

Multi-step reaction with 2 steps 1: Ac2O / CH2Cl2 / 3.5 h / Heating2: 1) Bu2SnO / 1) benzene, reflux, 24 h, 2) toluene, a) -40 deg C, 2 h, b) to r.t.