Figure 2: Reagents and reaction conditions: (a) i: K2CO3, MeOH, 25°C 1 h (83%, (formation of compound 1a); ii: CrO3, acetone, 25°C, 1 h (quant.); (b): Br2, AcOH, 25° C, 1.5 h; (c): LiCl, DMF, reflux, 1 h (67% for the 2 steps); (d) AcCl, Ac2O, reflux 50°C, 1 h (85%); (e): i: ethylene glycol, toluene, reflux, 3 h (quant.); ii: NaBH4, MeOH/THF (1/1), 25°C, 1.5 h ; iii: KOH, MeOH, reflux, 1 h (ii+iii: 60%); (f): Ac2O, pyridine, DMAP, CH2Cl2, 25°C, 2.5 h (80%); (g): Dess- Martin reagent, CH2Cl2, 0°C->25°C, 1 h (99%)