Cyclopentanone → (R)-Methyl 2-(cyclopentylamino)butanoate

Participants

Reaction Steps

The crude compound methyl (2R)-2-aminobutanoate 1j (11.24 g, 0.10 mol) and cyclopentanone (8.24 g, 0.10 mol) were dissolved in 150 mL of dichloromethane, stirred for 1.5 hours followed by the addition of sodium acetate (8.04 g, 0.10 mol) and sodium triacetoxyborohydride (30.52 g, 0.14 mol), and stirred for 3 hours. The reaction solution was poured into 150 mL 10% sodium bicarbonate solution, extracted with dichloromethane (100 mL×3). The combined organic phase was washed with saturated sodium chloride solution (100 mL×3), then dried over anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound methyl (2R)-2-(cyclopentylamino)butanoate 1k (6.04 g, yield: 34.0%) as a light liquid.

Provenance & Evidence