To a suspension 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 (0.2 g, 0.32 mmol) prepared in Example 190c in dioxane (10 mL) was added CuI (5 mg, 0.026 mmol) (Aldrich). The mixture was degassed under nitrogen for 5 min, then tris(dibenzylideneacetone)dipalladium(0) (23 mg, 0.026 mmol, Strem), tri-phenylphosphine (6.7 mg, 0.026 mmol), and tributyl(1-propynyl)tin (1.1 g, 3.2 mmol, Aldrich) were added sequentially. The reaction mixture was heated at 80° C. under nitrogen for 1 h. After cooled to room temperature, the reaction mixture was filtered through a short pad of celite. The filtrate was partitioned between saturated water and ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic layer was dried over Na2SO4 and concentrated. The residue was purified by chromatography to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-[2-(2-hydroxy-ethoxy)-5-(1-propynyl)-phenyl]spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a yellow solid (Yield 0.17 g, 99%).
