3-tetradecylthioacetylamino-1-triphenylmethyloxypropan-2-ol (example 20a) (2 g, 3.31 mmol) was dissolved in toluene (100 ml). Imidazole (0.564 g, 8.28 mmol), triphenylphosphine (2.171 g, 8.28 mmol) and iodine (1.681 g, 6.62 mmol) were then added in that order. The reaction medium was stirred at room temperature for 20 hours. A saturated sodium bisulfite solution was added until complete blanching of the reaction medium. The phases were separated and the aqueous phase was extracted with toluene. The organic phases were combined, washed with saturated sodium chloride solution, dried on magnesium sulfate and filtered. The residue obtained after evaporation of the solvent (4.65 g) was purified by chromatography on silica gel (eluent: dichiromethane) to give the desired compound in the form of a yellow oil.
