Benzaldehyde → methyl (2R)-2-(benzylamino)propanoate

Participants

Reaction Conditions

Reaction Steps

Benzaldehyde (19 mL, 19 g, 0.18 mol) was added to a solution of D-alanine methyl ester hydrochloride (25 g, 0.18 mol) in dry CH2Cl2 (300 mL). The solution was stirred at 22° C. for 19 h. The reaction mixture was cooled with an ice-water bath and solid sodium triacetoxyborohydride (46 g, 0.22 mol) was added in portions over ˜15 min. The cooling bath was removed and the milky white solution was stirred at 22° C. for 7 h. The solvent was removed by rotary evaporation under reduced pressure and the resulting slush was partitioned between EtOAc (˜100 mL) and 1 N HCl (˜400 mL). The aqueous layer was extracted with EtOAc (˜50 mL). The aqueous layer was adjusted to pH ˜10 with 1 N NaOH (450 mL) and the milky aqueous layer was extracted immediately with EtOAc (3×250 mL). The combined organic layers were washed with brine (˜250 mL), dried over anhydrous MgSO4, filtered and concentrated under reduced pressure to afford N-benzyl-D-alanine methyl ester (28 g, 80%) as a colorless semi-solid.

Provenance & Evidence