Dichloromethane → Methyl 2-methanesulfonyloxy-3-phenyl-propionate

Participants

Reaction Steps

To a stirred solution of phenylalanine (16.5 g, 0.1 mole) in 2N sulfuric acid at 0° C., was added sodium nitrite (10.5 g, 1.5 equiv) in small portions over a period of 0.5 hours and the mixture stirred overnight. Aqueous phase was extracted with ether (5×250 mL) and the ethereal extracts were washed with saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate and concentrated to give phenyllactic acid (1 equiv) in methanol (15 equiv) at 0° C. and the mixture stirred at room temperature overnight. Removal of volatiles in vacuo and chromatographic purification of the oil (20-25% ethyl acetate in hexane) gives methyl 2-hydroxy-3-phenylpropionate. 1H NMR (300 MHz, CDCl3): δ7.33-7.196 (m, 5H), 4.451 (dd, 1H), 3.764 (s, 3H), 3.1225 (dd, 4.45 Hz, 13.95 Hz, 1H), 2.9575 (dd, 7 Hz, 14 Hz, 1H), 2.787 (br s, 1H). A dichloromethane solution of methyl 2-hydroxy-3-phenylpropionate is treated with triethylamine (1.1 equiv) and methanesulfonyl chloride (1.1 equiv) at 0° C. Upon completion of reaction, the mixture is dissolved in dichloromethane/ether and washed with saturated aqueous solution of sodium chloride, dried and concentrated. Purification of crude material by flash column chromatography (40% ethyl acetate in hexane) gives methyl 2-methanesulfonyloxy-3-phenyl-propionate (1.6 g, 93%).

Provenance & Evidence