4-Phenylpiperidine (0.45 g, 2.78 mmol), palladium(II) acetate (0.016 g, 0.069 mmol), sodium tert-butoxide (0.34 g, 3.5 mmol) and BINAP (0.065 g, 0.104 mmol) were added to a solution of intermediate D3 (0.32 g, 1.39 mmol) in toluene (5 ml). The reaction mixture was heated at 100° C. for 16 hours in a sealed tube, after which it was cooled to room temperature, diluted with water (5 ml) and then extracted with EtOAc (3×5 ml). The combined organic fractions were dried (Na2SO4) and the solvent evaporated in vacuo. The crude product was purified by column chromatography (silica gel; 0-4% methanol/DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield intermediate D18 (0.33 g, 78%).
