The solution of diol (3 eq 150 mmol) in DCM (70 mL) was added slowly TEA (1.5 eq 75 mmol) for 5 mins at 0 °C. Then, the mixture was added TBSCl (1 eq, 50 mmol) at 0 °C and continue stirred at r.t for 12 hours. After reacted completely, the reaction was diluted by DCM (50 mL) and washed by H2O (3 x 50 mL). The combined organic layer was dried over anhydrous Na2SO4. After removal of the solvent, the crude residue was purified by column chromatography on silica gel with hexanes/EtOAc (4: 1) as the eluent to afford b as colorless oil (68% yield).