A solution of racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-[5-iodo-2-(2-hydroxy-ethoxy)-phenyl]spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione (0.15 g, 0.24 mmol) prepared in Example 190c in anhydrous N,N-dimethylformamide (10 mL) was added CuI (3 mg), 3,3-dimethyl-1-butyne (19.7 mg, 2.4 mmol) (Aldrich), and triethylamine (1 mL, 7.2 mmol). The mixture was degassed under nitrogen for 5 min, then dichlorobis(triphenylphosphine)palladium (8.4 mg, 0.012 mmol) (Strem) was added and the reaction mixture was heated at 80° C. under nitrogen for 0.5 h. The reaction mixture was cooled to room temperature and partitioned between ethyl acetate and water. The organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The organic layers were combined, dried over MgSO4 and concentrated. The residue was purified with chromatography to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-[5-(3,3-dimethyl-1-butynyl)-2-(2-hydroxy-ethoxy)-phenyl]spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a white solid (Yield: 41 mg, 30%).
