To a mixture of t-butyl 4-(4-fluoro-3-(trifluoromethylsulfonyloxy)phenyl)piperazine-1-carboxylate (0.50 g, 1.17 mmol) and (IR)-1-(2,4-dichlorophenyl)ethanamine (0.58 g, 3.05 mmol), tBuDavePhos (0.025 g, 0.070 mmol), and Cs2CO3 (0.80 g, 2.44 mmol) in triethylamine (3 mL) was purged with nitrogen for 3 min. Addition of Pd2(dba)3 (0.034 g, 0.037 mmol) was followed, and the mixture was purged with nitrogen for 1 min. The resulting mixture was heated at 100° C. under nitrogen for 4 h. After cooling to room temperature, the suspension was filtered through a plug of Celite, and washed with ethyl acetate (25 mL). The filtrate was concentrated in vacuo and the resulting residue purified by flash chromatography (SiO2, 10-50% ethyl acetate in hexanes) to afford (R)-t-butyl 4-(3-(1-(2,4-dichlorophenyl)ethylamino)-4-fluorophenyl)piperazine-1-carboxylate (0.36 g, 42.9 mmol, 62%).
