1: Et3N, DMAP / CH2Cl2 / 50 h / Heating 2: sodium phosphate, tetrabutylammonium periodate / CHCl3 / 24 h 3: 44 percent / sodium phosphate, m-CPBA / CHCl3 / 43 h / Ambient temperature 4: 30 percent / NaBH4 / methanol / 1.) 0 deg C, 12 h, 2.) RT, 24 h 5: 67 percent / sodium phosphate, tetrabutylammonium periodate / CHCl3 / 14 h / Ambient temperature 6: 75 percent / tetrabutylammonium fluoride / tetrahydrofuran / 1 h / Ambient temperature View Scheme

With  sodium tetrahydroborate; cerium(III) chloride in  ethanol T=0 - 20°C; 1.5 h;   

Multi-step reaction with 2 steps 1: Et3N, DMAP / CH2Cl2 / 50 h / Heating2: sodium phosphate, tetrabutylammonium periodate / CHCl3 / 24 h  

Multi-step reaction with 3 steps 1: Et3N, DMAP / CH2Cl2 / 50 h / Heating2: sodium phosphate, tetrabutylammonium periodate / CHCl3 / 24 h3: 44 percent / sodium phosphate, m-CPBA / CHCl3 / 43 h / Ambient temperature  

Multi-step reaction with 4 steps 1: Et3N, DMAP / CH2Cl2 / 50 h / Heating2: sodium phosphate, tetrabutylammonium periodate / CHCl3 / 24 h3: 44 percent / sodium phosphate, m-CPBA / CHCl3 / 43 h / Ambient temperature4: 30 percent / NaBH4 / methanol / 1.) 0 deg C, 12 h, 2.) RT, 24 h  

Multi-step reaction with 5 steps 1: Et3N, DMAP / CH2Cl2 / 50 h / Heating2: sodium phosphate, tetrabutylammonium periodate / CHCl3 / 24 h3: 44 percent / sodium phosphate, m-CPBA / CHCl3 / 43 h / Ambient temperature4: 30 percent / NaBH4 / methanol / 1.) 0 deg C, 12 h, 2.) RT, 24 h5: 67 percent / sodium phosphate, tetrabutylammonium periodate / CHCl3 / 14 h / Ambient temperature