To a stirred solution of 4-(4-benzofuranyl)-piperidine (0.3 g, 1.49 mmol) in dichloromethane (8 ml) was added at room temperature commercially available trans-tert-butyl-4-(2-oxoethyl)-cyclohexylcarbamate (1.71 mg, 6.02 mmol) and triethylamine (0.3 g, 0.42 ml, 2.98 mmol) and the solution was allowed to stir for 30 min. Sodium triacetoxyboron hydride (0.57 g, 2.68 mmol) was added step wise and the mixture was allowed to stir for 16 h at room temperature. The solution was poured into saturated sodium bicarbonate solution (20 ml) and extracted with dichloromethane (2×40 ml). The combined organic layers were washed with saturated sodium bicarbonate solution (20 ml), dried (MgSO4) and evaporated. The crude material (0.77 g) was purified by flash chromatography on silica gel (dichloromethane/MeOH 5-10%) to yield trans-{4-[2-(4-benzofuran-4-yl-piperidin-1-yl)-ethyl]-cyclohexyl}-carbamic acid tert-butyl ester as a white solid (0.63 g, 99%), MS (ISP) m/z=427.4 [(M+H)+], mp 133° C.
