C(C1(C(C)C)[O:8][C@@H:7]([CH2:9][CH2:10][OH:11])[CH2:6][O:5]1)(C)C.[CH2:15](Br)[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.[OH-].[Na+]>[I-].C([N+](CCCC)(CCCC)CCCC)CCC>[CH2:15]([O:11][CH2:10][CH2:9][C@H:7]([OH:8])[CH2:6][OH:5])[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1(S)-2,2-Diisopropyl-4-(2-hydroxyethyl)dioxolane (76.2 g, 0.377 mol), benzylbromide (129 g, 0.753 mol) and tetrabutylammonium iodide (7 g, 19 mmol) were mixed with a concentrated sodium hydroxide solution (40 g in 90 mL of water, 2.26 mol) in a 3-neck flask equipped with a mechanic stirrer and a condenser. After stirred at 110° C. for 18 hours, the mixture was cooled to room temperature and the organic layer was separated. The aqueous layer was extracted with methylene chloride (100 mL×2). The combined methylene chloride extrats were dried over magnesium sulfate. The solvent was evaporated, and the residue was treated with 300 mL of 1.5M sulfuric acid. After stirred at 100° C. for 8 hours, the mixture was cooled to room temperature, and hexane (300 mL) was added. The aqueous layer was washed with hexane twice (200 mL×2), and then ajusted pH to 8-9 with concentrated sodium sodium hydroxide. The solution was extrated with ethyl acetate (200 mL×3). The combined ethyl acetate extrates were dried over magnesium sulfate. The solvent was evaporated, and the residue was purified by fractional distillation in vacuo (0.1 mmHg, bp 150°-170° C.) to give 68.3 g (92% yield) of the title compound as an oil.
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