tert-Butyl methyl(piperidin-4-yl)carbamate (2.333 mmol, 1 eq) and 2-(pyrrolidin-1-yl)-isonicotinaldehyde (2.66 mmol, 1.14 eq) were dissolved in dichloromethane (15 ml), and acetic acid (5.459 mmol, 2.34 eq) and sodium triacetoxyborohydride (3.266 mmol, 1.4 eq) were added. The reaction mixture was stirred for 48 h at RT. When the reaction was complete (TLC monitoring), sat. sodium hydrogen carbonate solution was added to the reaction mixture and the phases were separated. The aqueous phase was extracted with dichloromethane (2×30 ml). The combined organic phases were washed with sat. NaCl solution, dried over sodium sulfate and concentrated. The crude product was purified by column chromatography (silica gel, ethyl acetate:cyclohexane 2:1). Yield: 64%.
