Potassium hydroxide (2.00 g) was added to a solution of diethyl 2-(4-benzyloxybenzyl)-2-(3-phenylpropyl)malonate (3.91 g) in a mixture of 2-methoxyethanol (30 ml) and water (3 ml). The mixture was stirred at 130° C. in an oil bath for 1.5 hours. At the end of this time the reaction mixture was partitioned between ethyl acetate and water and the mixture was acidified with aqueous hydrogen chloride solution (6N). The ethyl acetate layer was separated and washed with aqueous sodium chloride solution and dried over anhydrous magnesium sulfate and concentrated. A solution of the residual syrup in xylene (20 ml) was stirred for 1 hour and then concentrated. Concentrated sulfuric acid (1 ml) was added to a solution of the syrup residue of 2-(4-benzyloxybenzyl)-5-phenylvaleric acid in ethanol (40 ml). The mixture was stirred at 80° C. for 3 hours and allowed to stand at ambient temperature for 16 hours. At the end of this time the reaction mixture was concentrated and the residue was partitioned between ethyl acetate and water. The ethyl acetate layer was separated and dried over anhydrous magnesium sulfate and concentrated to dryness to afford the desired compound (3.32 g) as a syrup.
