Dissolve (4-bromo-2-fluoro-phenyl)acetic acid (1.49 g, 6.39 mmol) in 25 mL amylene-stabilized chloroform and add hydroxybenzotriazole hydrate (0.95 g, 7.03 mmol), to give a slurry. Add 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (1.47 g, 7.67 mmol) and stir the resulting clear solution at room temperature for 15 minutes. Add [1-(3-amino-phenyl)-1-methyl-ethyl]-carbamic acid tert-butyl ester and stir for 90 minutes at room temperature. Dilute reaction with 20 mL dichloromethane and wash with saturated NaHCO3, 1 N NaHSO4, and dilute aqueous saturated sodium chloride, then dry over MgSO4 and concentrate to give a brittle tan foam. Purify the foam on a 120 g silica cartridge with 100% CH2Cl2 for 5 minutes followed by a gradient of 0→10% EtOAc in CH2Cl2 over 40 minutes. Concentrate and dry clean fractions to provide 2.11 g (71%) of the title compound as a brittle white foam. LCMS (ES) m/z 463/465 (M−1).
