1: 3,5-di-O-benzyl-1,2-O-isopropylidene-4-C-methanesulfonyloxymethyl-α-D-ribofuranose With water; acetic acid T=90°C; Hydrolysis; 3 h; 2: acetic anhydride With pyridine T=20°C; Acetylation; 12 h;

1: 95 percent / HCl, H2O 2: 97 percent / pyridine 3: 66 percent / Me3SiOTf / CH2Cl2 4: NH3 / methanol 5: NaH / dimethylformamide 6: 1.) HMDS, 2.) NBS, molecular sieves 4 Angstroem / 2.) CH2Cl2 7: 12 percent / H2 / Pd(OH)2/C / ethanol View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1.1: dibutyltin oxide / methanol / 1 h / Heating<br />1.2: 19 percent / Bu₄NBr / toluene / 15 h / Heating<br />2.1: 92 percent / pyridine<br /> <br /> &nbsp;