To a stirred solution of (S)-4-[2-(4-amino-phenyl)-ethyl]-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (150 mg, example 6b) in dry THF (0.2 ml) under an argon atmosphere was added sodium hydride (34 mg, 60% dispersion in mineral oil) and stirring was continued for 15 minutes. Trifluoro-methanesulfonic acid 1-(5-bromo-pyridin-2-yl)-2,2,2-trifluoro-ethyl ester (182 mg) was then added and the mixture was stirred overnight at room temperature. The reaction mixture was diluted with ethyl acetate and washed sequentially with water and with saturated brine. The organic phase was separated, 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-[1-(5-bromo-pyridin-2-yl)-2,2,2-trifluoro-ethylamino]-phenyl}-ethyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (99 mg, 38%) as a yellow oil. MS (ISP): 560.1 ([{81Br}M+H]+), 558.1 ([{79Br}M+H]+).
