Cesium carbonate → 4-{[(2R,3S,4R,5S)-3-(3-chloro-2-fluoro-phenyl)-4-(4-chloro-2-fluoro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carbonyl]-amino}-3-methoxy-benzoic acid di-tert-butoxy-phosphoryloxymethyl ester

Participants

Reaction Steps

To a solution of chiral 4-((2R,3S,4R,5S)-3-(3-chloro-2-fluorophenyl)-4-(4-chloro-2-fluorophenyl)-4-cyano-5-neopentylpyrrolidine-2-carboxamido)-3-methoxybenzoic acid (prepared as described in US20100152190A1, 200.0 mg, 0.324 mmol) in dimethylformamide (8 mL) was added cesium carbonate (529 mg, 1.62 mmol). The mixture was stirred for ˜20 min before di-tert-butyl chloromethyl phosphate (TCI, 236 mg, 0.9912 mmol) in dimethylformamide (1 mL) was added. The reaction mixture was allowed to stirr at room temperature for 3 h before it was partitioned between ethyl acetate and water, washed with water and dried over anhydrous sodium sulfate and concentrated. The crude product was purified by flash chromatography (hexane/ethyl acetate, 85/15 to 5/95) to give chiral 4-{[(2R,3S,4R,5S)-3-(3-chloro-2-fluoro-phenyl)-4-(4-chloro-2-fluoro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carbonyl]-amino}-3-methoxy-benzoic acid di-tert-butoxy-phosphoryloxymethyl ester as a white solid (192 mg, 70% yield). LCMS (ES+) m/z calcd. for C40H49Cl2F2N3O8P [(M+H)+]: 838, found: 838.

Provenance & Evidence