A mixture of piperazine-1-carboxylic acid tert-butyl ester (2.02 g), 1-(4-bromophenyl)-4-phenylpiperidine (2.86 g), tris(dibenzylideneacetone)(chloroform)-di-palladium(0) (0.19 g), (S)-(−)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (0.28 g) and sodium tert-butoxide (1.74 g) in toluene (29 ml) was stirred for 6 hours at 90° C. The reaction mixture was added to a mixture of water and ethyl acetate. The organic layer was taken and dried over magnesium sulfate. The magnesium sulfate was filtered off, and the filtrate was evaporated under reduced pressure. The residue was purified by column chromatography over silica using dichloromethane/methyl alcohol (50:1) as the elution to give 4-[4-(4-phenylpiperidin-1-yl)phenyl]piperazine-1-carboxylic acid tert-butyl ester (2.93 g).
