Ammonium Chloride → 3-Cyclopentyl-1-(2,6-dimethylphenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

LHMDS (1 M solution in THF, 2.4 mL, 2.4 mmol) was added slowly to a cooled (−50° C.) solution of 1-(2,6-dimethylphenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester (494 mg, 2 mmol) in THF (5 mL). Stirred at −50° C. for 5 min then warmed to 0° C. and stirred further for 5 min. After cooling back to −50° C., iodocyclopentane (462.5 μL, 4 mmol) was added and the resulting reaction mixture was warmed to room temperature and stirred for 2 h. Saturated aqueous NH4Cl solution (10 mL) was added, and the aqueaous solution was extracted with EtOAc (3×25 mL). The combined organic layer was washed with water (50 mL), brine (50 mL), dried (Na2SO4) and evaporated. The residue was purified by flash chromatography (SiO2, 20→50% EtOAc/hexanes) to give 3-cyclopentyl-1-(2,6-dimethylphenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester (120 mg, 19% yield). LC-MS: Rt (retention time): 2.54 min, MS: (ES) m/z 316.4 (M+H+).

Provenance & Evidence