Triethylamine → 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

Participants

Reaction Steps

To a solution of [3,3-dimethyl-but-(E)-ylideneamino]-acetic acid tert-butyl ester (4.26 g, 20.00 mmol) and (Z)-3-(3-chloro-phenyl)-2-(4-chloro-phenyl)-acrylonitrile (5.48 g, 20.00 mmol) in ClCH2CH2Cl (100 mL) were added triethyl amine (4.2 g, 40.00 mmol) and AgF (2.53 g, 20.00 mmol) in one portion. The mixture was stirred at rt overnight. The mixture was then quenched with sat. NH4Cl and extracted with CH2Cl2. The organic phase was separated, filtered through Celite and dried over Na2SO4. The mixture was then separated and concentrated. The residue was triturated with EtOAc and nHexane, and the precipitates were collected by filtration and the mother liquid was concentrated and further purified by flash column (SiO2, 1-20% of EtOAc in hexanes) 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 tert-butyl ester (6.65 g, 68.2%; HRMS (ES+) m/z Calcd for C27H32Cl2N2O2+H [(M+H)+]: 487.1914. found: 487.1910.) and 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 (0.86 g, 8.8%).

Provenance & Evidence