To a dimethyl sulfoxide (0.6 mL) solution of tertiary butoxy potassium (40.3 mg, 0.359 mmol), a dimethyl sulfoxide (0.8 mL) solution of 7-methoxy-3-phenyl-4-(4-pivaloyloxyphenyl)-3,4-dihydronaphthalene (6, 29.3 mg, 0.0710 mmol) was added, and stirred at room temperature for one day and night. After adding saturated ammonium chloride (10 mL) to the reaction mixture with much stirring, extraction was carried out three times with diethyl ether. The organic layers were combined, washed with a saturated sodium chloride solution (10 mL), and after drying with anhydrous sodium sulphate, concentrated. The residue was purified with thin layer chromatography (toluene:ethyl acetate=10:1), to obtain the subject compound (7, 16.0 mg; yield=69%).
