Ethyl p-methylbenzenesulfonate → Methyl (3S*,4R*)-4-(2,4-difluorophenyl)-1-ethylpyrrolidine-3-carboxylate

Participants

Reaction Steps

A mixture of methyl (3S,4R)-4-(2,4-difluorophenyl)pyrrolidine-3-carboxylate from Preparation 31 (500 mg, 2.07 mmol), ethyl tosylate (519 mg, 2.59 mmol) and potassium carbonate (573 mg, 4.15 mmol) were heated in acetonitrile at 70° C. for 16 hours under nitrogen. The reaction mixture was then cooled to room temperature and concentrated in vacuo. The residue was dissolved in dichloromethane (30 ml) and partitioned with saturated aqueous sodium bicarbonate (30 ml). The organic layer was then washed with brine (20 ml), dried over magnesium sulfate, filtered, and the solvent was removed in vacuo. The above procedure was performed in duplicate. The crude products from the two reactions were then combined and purified by column chromatography on silica eluting with dichloromethane:methanol (99:1) to give the title compound as a pale yellow oil, 968 mg.

Provenance & Evidence