To a mixture of 2.3 mg of tris(dibenzylideneacetone)dipalladium(0), 1.9 mg of 2-(dicyclohexylphosphino)-2′-(dimethylamino)biphenyl, and 0.5 mL of 1,4-dioxane were added 100 mg of tert-butyl[(1R)-1-(1-naphthyl)ethyl][(3-phenylpiperidin-4-yl)methyl]carbamate, 83.8 mg of ethyl 3-iodobenzoate, 105 mg of cesium carbonate, 1.0 mL of 1,4-dioxane, and 1.5 mL of t-butanol, followed by stirring at 100° C. overnight. After cooling to room temperature, to the reaction mixture was added ethyl acetate, the insolubles were removed, and the solvent was removed by distillation under reduced pressure. The residue was purified by silica gel column chromatography (hexane-ethyl acetate) to obtain 108 mg of ethyl 3-[4-({(tert-butoxycarbonyl)[(1R)-1-(1-naphthyl)ethyl]amino}methyl)-3-phenylpiperidin-1-yl]benzoate as a pale yellow foamy substance. ESI+: 593
