The condensation of (R)-1-amino-3-phenyl-2-propanol (I) with 1-phenyl-3-(4-morpholinyl)-1-propanone (II) in benzene with azeotropic removal of water furnished the intermediate imine (III), which was reduced employing tetramethylammonium triacetoxyborohydride to produce aminoalcohol (IV) as a 2:1 diastereomeric mixture. Treatment of this mixture with ethyl chloroformate gave a mixture of carbamates, from which the required (1S,2R)-diastereoisomer (V) was isolated by recrystallization as the methanesulfonate salt. Cyclization of (V) with K2CO3 then yielded oxazolidinone (VI). This was finally treated with fumaric acid to provide the title fumarate salt.