To a solution of trifluoro-methanesulfonic acid 4-[1-benzyl-4-(3-methoxy-phenyl)-piperidin-4-yl]-phenyl ester (10.0 g, 19.8 mmol) in a Parr pressure bottle in MeOH (69 mL) were added DMSO (62 mL) and triethylamine (21.8 mL, 157 mmol). To the reaction mixture were added palladium acetate (2.2 g, 9.1 mmol) and 1,3-bis(diphenylphosphino)propane (3.75 g, 9.1 mmol). The mixture was shaken under 40 psi of CO at 70° C. for 4 hours. The reaction mixture was cooled to room temperature and was diluted with diethyl ether (600 mL). The ether layer was washed with water (5×60 mL), dried (MgSO4) and concentrated. The crude residue was purified by flash chromatography with hexanes/EtOAc (1:1) to afford 6.9 g (85% yield) of 4-[1-Benzyl-4-(3-methoxy-phenyl)-piperidin-4-yl]-benzoic acid methyl ester. 1HNMR (400 MHz, CDCl3) δ 7.91 (d, 2H), 7.32 (d, 2H), 7.28-7.16 (comp, 6H),), 6.82 (d, , 1H), 6.79 (s, 1H), 6.68 (dd, 1H), 3.86 (s, 3H), 3.74 (s, 3H), 3.38 (s, 2H), 2.47-2.44 (comp, 8H); MS (M+1) 416.2.
