Lithium borohydride → rac-(4R,5S)-4-(hydroxymethyl)-1-(4-methoxybenzyl)-5-methylpyrrolidin-2-one

Participants

Reaction Steps

Lithium borohydride (3.5 g, 0.16 mol) in THF (50 mL) was slowly added dropwise to a solution of ethyl rac-(2R,3S)-1-(4-methoxybenzyl)-2-methyl-5-oxopyrrolidine-3-carboxylate (18.5 g, 0.064 mol) in THF (350 mL) at 0° C. The reaction mixture was allowed to stir at room temperature for 16 hours and then quenched by the slow addition of saturated aqueous ammonium chloride solution (30 mL). After removal of THF under reduced pressure, the mixture was diluted with water (100 mL) and extracted with ethyl acetate (300 mL×3). The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (ethyl acetate/petroleum ether) to give rac-(4R,5S)-4-(hydroxymethyl)-1-(4-methoxybenzyl)-5-methylpyrrolidin-2-one. MS ESI calc'd. for C14H20NO3 [M+H]+ 250. found 250. 1H NMR (CDCl3, 400 MHz): δ 7.10 (d, J=8.4 Hz, 2H), 6.79 (d, J=8.4 Hz, 2H), 4.83 (d, J=14.8 Hz, 1H), 3.85 (d, J=14.8 Hz, 1H), 3.74 (s, 3H), 3.47 (d, J=6.4 Hz, 2H), 3.30-3.27 (m, 1H), 2.76 (s, br, 1H), 2.58-2.52 (m, 1H), 2.24-2.18 (m, 1H), 2.06-2.02 (m, 1H), 1.15 (d, J=6.4 Hz, 3H).

Provenance & Evidence