Scheme 2.

Reagents and conditions a) Ac₂O, dry pyridine, 99%; b) HBr/CH₃COOH, CHCl₃, 2 h, RT, 64%; c) NaN₃, acetone, 60 °C, 94%; d) BzCl, dry pyridine, 0 °C, Argon; e) 2-Methyl-5-tert-butylthiophenol, BF₃.Et₂O, dry CH₂Cl₂, Argon, 74%; f) 3-bromo-propan-1-ol, NBS, TfOH, 4 Ǻ molecular sieves, dry CH₂Cl₂, Argon, 72%; g) NaN₃, dry DMF, 60 °C, 81%; h) Na, dry MeOH, 82%; i) Ac₂O, dry pyridine, 85%