Sodium Carbonate → (1R)-(+)-(1-benzyloxycarbonylamino-2-methylpropyl)phosphonic acid

Participants

Reaction Steps

A slurry of (1R)-(+)-(1-amino-2-methylpropyl)phosphonic acid (2.57 g, 16.8 mmol), NaHCO3 (2.82 g, 33.6 mmol), and Na2CO3 (3.58 g, 33.8 mmol) in 16 mL of 2N NaOH and 3 mL of H2O was cooled in an ice water bath. To this was added benzyloxycarbonyl chloride (2.4 mL, 16.8 mmol). During the next 2 hours, two additional aliquots of benzyloxycarbonyl chloride were added (2.4 mL each). After stirring at ambient temperature for 16 hours, 40 mL of 2N NaOH was added and the mixture was partitioned between water and ether. The aqueous portion was washed with ether, acidified to pH 2 with concentrated HCl, and extracted with ethyl acetate (2×) and with methylene chloride (2×). The combined organic extracts were washed with saturated NaCl, dried over MgSO4, filtered, and concentrated in vacuo to give 4.41 g (91%) of (1R)-(+)-(1-benzyloxycarbonylamino-2-methylpropyl)phosphonic acid as a white foam.

Provenance & Evidence