[C:1]([N:6]1[CH2:10][CH2:9][O:8][C:7]1=[O:11])(=[O:5])/[CH:2]=[CH:3]/[CH3:4].[NH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.CS(O)(=O)=O>C(OCC)(=O)C>[C:13]1([NH:12][CH:3]([CH3:4])[CH2:2][C:1]([N:6]2[CH2:10][CH2:9][O:8][C:7]2=[O:11])=[O:5])[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1To a solution of 3-crotonoyl-1,3-oxazolidin-2-one (155 mg, 1.0 mmol) in ethyl acetate (3 ml) in a stream of nitrogen was added Pd((R)-binap)(H2O)2(OTf)2 (26.6 mg, 0.025 mmol), and the resulting mixture was cooled to 0° C. Aniline (0.11 ml, 1.2 mmol) was added to the mixture, and to the solution was added slowly methanesulfonic acid (0.078 ml, 1.2 mmol). Then, the cooling ice-bath was removed and the reaction mixture was reacted at room temperature for 18 hours with stirring. After completion of the reaction, the solvent was evaporated off, and the crude product obtained was purified by a silica gel column chromatography (hexane:ethyl acetate=1:1) to give the objective compound 3-(3-phenylaminobutyryl)-oxazolidin-2-one (37 mg, 15% yield). Enantiomeric excess ratio of this product was determined by a liquid chromatography using a column for separation of optical isomers (column: AD-H) to be 82% e.e.
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