(S)-4-O-Benzyl-1,2,4-butanetriol (68.3 g, 348 mmol) was mixed with triethylamine (70.4 g, 696 mmol) and dimethylaminopyridine (3.42 g, 28 mmol) were mixed in methylene chloride (300 mL) under nitrogen atmosphere. To the solution p-anisylchlorodiphenylmethane (129.1 g, 418 mmol) was added at 0° C. The reaction mixture was stirred at 0° C. for 30 min and then at room temperature for 5 hours. Saturated sodium bicarbonate was added to the mixture and the resulting mixture was stirred at room temperature for 1 hour. The aqueous layer was extracted with methylene chloride (150 mL×2). The combined methylene chloride extracts were dried over mganesium sulfate. The solvent was evaporated, and the residue was purified by flash chromatography on silica gel (ethyl acetate:hexane=1:5 to 1:1) to give 155.5 g (95% yield) of the title compound as a thick oil.
