Acetic Anhydride → (3R)-3-amino-3-phenylpropanoic acid

(±)-3-Amino-3-phenylpropanoic acid (2.378 g, 14.4 mmol), 2.0 ml of acetic acid, and 236 mg (2.88 mmol) of anhydrous sodium acetate were charged into a 30-ml two-necked round-bottomed flask equipped with a stirrer and a calcium chloride tube and cooled down to a temperature not higher than 10° C. using an ice bath. Acetic anhydride (4 ml, 42.8 mmol) cooled to a temperature of not higher than 10° C. was added dropwise to the solution, and the mixture was stirred for 40 minutes at that temperature and then stirred for 80 minutes at room temperature.