2-Pyrrolidone → (2R,5S)-4-Benzyl-2-methyl-5-(2-oxo-pyrrolidin-1-ylmethyl)-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

Three separate reaction flasks were each charged with sodium hydride (60% in mineral oil, 0.486 g, 12.16 mmol) and anhydrous DMF (40.5 mL). To these, pyrrolidinone (0.924 mL, 12.16 mmol) was added dropwise. After stirring at this temperature for 30 minutes, (2R,5R)-4-benzyl-5-chloromethyl-2-methyl-piperazine-1-carboxylic acid tert-butyl ester (2.74 g, 8.11 mmol) was added to each at room temperature. The reactions were stirred at 80° C. for 4 h. The reactions were combined and saturated aqueous sodium bicarbonate was added and the mixture extracted with diethyl ether (3×). The combined organic layers were washed with brine, dried with sodium sulfate, filtered and concentrated. Chromatography (silica gel, gradient elution, 0-100%, EtOAc in petrol 40-60) gave the title compound (5.9 g), MS: [M+H]+=388.

Provenance & Evidence