(4R,5R)-4-methyl-5-phenyl-1,3-oxazolidin-2-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 27.4 g of (4R,5R)-4-methyl-5-phenyl-2-oxazolidinone in 200 cm3 of dry tetrahydrofuran are added, at -78° C., 100 cm3 of a 1.6M butyllithium solution in hexane, followed by addition of 33.12 g of a solution of 2-methoxyphenylacetic acid in 30 cm3 of tetrahydrofuran. The mixture is stirred for 30 minutes at this temperature and then allowed to return to room temperature. 200 cm3 of saturated aqueous ammonium chloride solution are subsequently poured in, followed by 200 cm3 of ethyl acetate. The organic phase is washed three times with 300 cm3 of water, and then with 300 cm3 of saturated aqueous sodium chloride solution, and dried over magnesium sulphate and concentrated to dryness under reduced pressure (2.7 kPa). The residue is taken up in 100 cm3 of diethyl ether. 35.5 g of (4R,5R)-4-methyl-5-phenyl-3-[(2-methoxyphenyl)acetyl]-2-oxazolidinone are obtained, in the form of white crystals melting at 126° C. to return to room temperature The organic phase is washed three times with 300 cm3 of water with 300 cm3 of saturated aqueous sodium chloride solution, and dried over magnesium sulphate concentrated to dryness under reduced pressure (2.7 kPa)