Triethylamine → racemic (2'R,3R,4'S)-6-chloro-4'-(3-chlorophenyl)-2'-(3-ethynyl-phenyl)spiro[3H-indole-3,3'-piperidine]-2,6'(1H)-dione

Participants

Reaction Conditions

Reaction Steps

A solution of racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(3-iodophenyl)spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione (0.56 g, 1 mmol) prepared in example 192b in anhydrous tetrahydrofuran (30 mL) was added trimethylsilyl acetylene (0.1 g, 2.0 mmol) (Aldrich), CuI (0.38 g, 2.0 mmol) (Aldrich) and triethylamine (0.2 g, 2.0 mmol) was degassed under nitrogen for 5 min, then dichlorobis(triphenylphosphine)palladium(0) (140 mg, 0.2 mmol) (Strem) was added and the reaction mixture was heated at 100° C. under nitrogen for 3 h. The reaction mixture was cooled to room temperature and filtered through a short pad of silica gel, the silica gel was washed with ethyl acetate. The filtrate was concentrated. To the residue was added methanol (10 mL) and aqueous NaOH solution (1 N, 2 mL). The mixture was stirred at room temperature for 2 h, then 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 (EtOAc:hexanes=2:1) to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(3-ethynyl-phenyl)spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a white solid (Yield: 0.24 g, 52%).

Provenance & Evidence