Ammonium Chloride → 3-Benzyloxymethyl-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, 9.72 mL, 9.72 mmol) was added slowly to a cooled (−50° C.) solution of 1-(2,6-dimethylphenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester (2 g, 8.09 mmol) in THF (50 mL). The solution was stirred at −50° C. for 5 min then warmed to 0° C. and stirred for a further 5 min. After cooling back to −50° C., BOMCl (˜90% pure, 2.46 mL, 17.8 mmol) was added and the resulting reaction mixture was warmed to room temperature and stirred for 2 h. Saturated aqueous NH4Cl solution (25 mL) was added, and the aqueous solution was extracted with EtOAc (3×75 mL). The combined organic layer were washed with water (100 mL), brine (100 mL), dried (Na2SO4) and evaporated. The residue was purified by automated flash chromatography (SiO2, 10→50% EtOAc/hexanes) to give 3-benzyloxymethyl-1-(2,6-dimethylphenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester (653 mg, 22% yield). LC-MS: Rt (retention time): 2.72 min, MS: (ES) m/z 368.1 (M+H+).

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