A mixture of (S)-[1-(3-bromophenyl)ethyl]carbamic acid tert-butyl ester (5.0 g, 16.7 mmol), 1-pyridin-2-ylpiperazine (10.9 g, 67 mmol), Pd2(dba)3 (1.55 g, 10 mol %), di-t-butyl-biphenylphosphine (0.51 g, 10 mol %), potassium phosphate (7.2 g, 34 mmol) in ethyleneglycol dimethyl ether (40 mL) was refluxed for 4 h. After cooling to room temperature, the reaction mixture was diluted with dichloromethane (100 mL) and the precipitate was filtered off. The filtrate was concentrated under vacuum. The crude product was purified by flash chromatography over silica with ethyl acetate/hexanes (1:2) to provide the title compounds as an oil (4.1 g, 64% yield).
