Toluene → rac-(2'S,3'S,4'S)-6-chloro-2'-(3-chloro-2-fluoro-phenyl)-4'-(2,2-dimethyl-propyl)-2-oxo-1,2-dihydro-spiro[indole-3,3'-pyrrolidine]-1'-carbonyl chloride

Participants

Reaction Steps

To a solution of rac-(2′S,3′S,4′S)-6-chloro-2′-(3-chloro-2-fluoro-phenyl)-4′-(2,2-dimethyl-propyl)-1H-spiro[indole-3,3′-pyrrolidin]-2-one prepared in Example 6 (0.12 g, 0.28 mmol) in dichloromethane (3 mL) was added saturated aqueous NaHCO3 solution (3 mL). The temperature of the mixture was lowered to 0° C., and a toluene solution (Aldrich, 20%) of phosgene (0.27 mL, 0.51 mmol) was added dropwise via a syringe. The reaction mixture was stirred at room temperature for 30 min, then diluted dichloromethane. The organic layer was separated, the aqueous layer was extracted with dichlormethane twice. The combined organic layers were washed with water, brine, dried over MgSO4, and concentrated to give crude rac-(2′S,3′S,4′S)-6-chloro-2′-(3-chloro-2-fluoro-phenyl)-4′-(2,2-dimethyl-propyl)-2-oxo-1,2-dihydro-spiro[indole-3,3′-pyrrolidine]-1′-carbonyl chloride as a light yellow oil, which was used in the next step without further purification (0.14 g, 100%).

Provenance & Evidence