A (4-oxo-cyclohexyl)-carbamic acid tert-butyl ester Compound 1b (1.54 g, 7.21 mmol), NaBH(OAc)3 (64.45 g, 21.0 mmol) and HOAc (0.3 mL) were added to a solution of 4-(2-isopropoxy-phenyl)-piperidine Compound 1a (1.32 g, 6.01 mmol) in CH2Cl2 (100 mL). The mixture was stirred under N2 for two days, then the reaction was quenched with MeOH. The mixture was evaporated and the resulting residue was redissolved with CH2Cl2, washed using 10% aqueous Na2CO3 and brine, then dried (Na2SO4). The crude product was purified by column chromatography to provide {4-[4-(2-isopropoxy-phenyl)-piperidin-1-yl]-cyclohexyl}-carbamic acid tert-butyl ester Compound 1c as a mixture of cis/trans isomers (MS 416; yellowish oil; 1.19 g, 48% yield).
