rac-(2R,3R,4R,5R)-3-(3-chloro-phenyl)-4-(4-chloro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carboxylic acid tert-butyl ester → rac-(2R,3R,4R,5S)-3-(3-chloro-phenyl)-4-(4-chloro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carboxylic acid

Participants

Reaction Steps

A solution of rac-(2R,3R,4R,5S)-3-(3-chloro-phenyl)-4-(4-chloro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carboxylic acid tert-butyl ester (3.78 g, 7.75 mmol) in conc. H2SO4 (20 mL) was stirred at rt for 2 hrs. The mixture was then poured into ice and extracted with EtOAc. The organic phase was separated, dried over Na2SO4, and concentrated. The residue was then triturated with EtOAc and nHexane and the precipitates were collected by filtration and washed with ether to give rac-(2R,3R,4R,5S)-3-(3-chloro-phenyl)-4-(4-chloro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carboxylic acid (3.60 g, 100%) as a white solid which was used in the next step without further purification: HRMS (ES+) m/z Calcd for C23H24Cl2N2O2+H [(M+H)+]: 431.1288. found: 431.1287.

Provenance & Evidence