To rac-(2R,3S,4R,5S)-3-(3-chloro-2-fluoro-phenyl)-4-(4-chloro-2-fluoro-phenyl)-4-cyano-5-(2-cyclopropyl-2-methyl-propyl)-pyrrolidine-2-carboxylic acid methyl ester prepared in Example 99b (0.95 g, 1.87 mmol) in tetrahydrofuran (40 mL) was added an aqueous solution (20 mL) of NaOH (0.15 g, 3.7 mmol) and methanol (20 mL). The reaction mixture was stirred at room temperature for 18 h. The “pH” of the mixture was adjusted to 5 by aqueous HCl solution. The mixture was concentrated. The residue was partitioned between ethyl acetate and water. The organic layer was separated, washed with water, brine, dried over MgSO4, concentrated, and trituated with dichloromethane and hexanes to give rac-(2R,3S,4R,5S)-3-(3-chloro-2-fluoro-phenyl)-4-(4-chloro-2-fluoro-phenyl)-4-cyano-5-(2-cyclopropyl-2-methyl-propyl)-pyrrolidine-2-carboxylic acid as a white solid (0.78 g, 80%)
