Ethyl 2-(4-benzyloxyphenyl)-4,5,6,7-tetramethoxy-1-oxo-2-indancarboxylate (3.78 g, 7.46 mmols) was dissolved in ethanol (40 mmols), and sodium borohydride (564 mg, 14.9 mmols) was added thereto with cooling with ice. The reaction mixture was warmed to room temperature, and then stirred for further 6 hours. Water was added to the reaction mixture, which was neutralized with 10% hydrochloric acid, and then extracted with ethyl acetate. The organic layer was washed with water and a saturated aqueous sodium chloride solution, and then dried. The solvent was evaporated out in vacuo, and the resulting crude product was purified by silica gel column chromatography (hexane:ethyl acetate=4:1 to 2:1) to obtain ethyl 2-(4-benzyloxyphenyl)-1-hydroxy-4,5,6,7-tetramethoxy-2-indancarboxylate (3.02 g).
