[C:1]([O:5][C:6]([N:8]1[C@@H:12](/[CH:13]=[CH:14]/[C:15]2[CH:20]=[CH:19][C:18]([N+:21]([O-])=O)=[CH:17][CH:16]=2)[CH2:11][O:10][C:9]1([CH3:25])[CH3:24])=[O:7])([CH3:4])([CH3:3])[CH3:2].C([O-])=O.[NH4+]>CO.[Pd]>[C:1]([O:5][C:6]([N:8]1[C@@H:12]([CH2:13][CH2:14][C:15]2[CH:16]=[CH:17][C:18]([NH2:21])=[CH:19][CH:20]=2)[CH2:11][O:10][C:9]1([CH3:25])[CH3:24])=[O:7])([CH3:4])([CH3:2])[CH3:3]To a stirred suspension of (S)-2,2-dimethyl-4-[(E)-2-(4-nitro-phenyl)-vinyl]-oxazolidine-3-carboxylic acid tert-butyl ester (12.0 g) in methanol (500 ml) were added ammonium formate (32.6 g) and palladium on charcoal (1.83 g, 10 wt %) and the mixture was heated at 50° C. for 1 hour. The mixture was then cooled to room temperature, filtered through celite and the filtrate was concentrated in vacuo. The residue was then taken up in ethyl acetate and washed with water. The phases were separated and the organic phase was dried over sodium sulphate and concentrated in vacuo. The reside was purified by column chromatography (SiO2; gradient: heptane/EtOAc) to give (S)-4-[2-(4-amino-phenyl)-ethyl]-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (8.72 g, 79%) as a yellow oil. MS (ISP): 321.4 ([M+H]+).
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