[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([NH2:9])=[CH:5][CH:4]=1.FC(F)(F)S(O)(=O)=O.[C:18]([N:23]1[CH2:27][CH2:26][O:25][C:24]1=[O:28])(=[O:22])/[CH:19]=[CH:20]/[CH3:21].[Cl-].[NH4+]>C1(C)C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([NH:9][CH:20]([CH3:21])[CH2:19][C:18]([N:23]2[CH2:27][CH2:26][O:25][C:24]2=[O:28])=[O:22])=[CH:5][CH:4]=1A solution of anisidine (55.4 mg, 0.45 mmol) in toluene (1.5 ml) was cooled to 0° C., and trifluoromethanesulfonic acid (40 μL, 0.45 mmol) was added dropwise. The mixture was stirred for 10 minutes, and to this solution were added Pd((R)-binap)(OH2)2(OTf)2 (8 mg, 0.00752 mmol) and 3-crotonoyl-1,3-oxazolidin-2-one (47 mg, 0.3 mmol). The ice-cooling bath was removed and the mixture was reacted at room temperature for 20 hours. A saturated aqueous solution of ammonium chloride was added to quench the reaction, and the reaction mixture was extracted with ethyl acetate. The organic layer was concentrated and purified by a silica gel column chromatography (hexane:ethyl acetate=4:1) to give the objective 3-[3-(4-methoxyphenylamino)butyryl]-1,3-oxazolidin-2-one (66.5 mg, 96% yield). The enantiomeric excess was determined by a liquid chromatography with an optical isomer separating column (column: AD-H) to be 94% e.e.
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