6-{2-[2,4-dichloro-6-(2-methoxyethoxymethoxy) phenyl]ethyl}-3,4,5,6-tetrahydro-4-hydroxy-2H-pyran-2-one → 6-{2-(2,4-Dichloro-6-hydroxyphenyl)-ethyl}-3,4,5,6-tetrahydro-4-hydroxy-2H-pyran-2-one

Zinc bromide (2.4 g, 10 mmole) was added to a solution of 6-{2-[2,4-dichloro-6-(2-methoxyethoxymethoxy) phenyl]ethyl}-3,4,5,6-tetrahydro-4-hydroxy-2H-pyran-2-one (780 mg, 2 mmole) in methylene chloride (12 ml). The resulting mixture was stirred at 20° C. for 2 hours, then quenched with saturated sodium bicarbonate solution (50 ml) and diluted with ether (200 ml). The ethereal layer was washed with brine, dried over MgSO4, filtered and evaporated. The residue was chromatographed on a 50 mm low-pressure column with 6 inches of silica gel (230-400 mesh). The column was eluted with 470 ml of methylene chloride-acetone (4:1, v:v). The next 330 ml provided the title compound as a golden glass (100 mg., 16%): pmr (CDCl3) δ2.62 (2H, d), 4.29 (H, m), 4.78 (H, m), 6.87 (2H, s).