To a suspension of 1-[3-(1H-benzoimidazol-2-yl)-4-chloro-phenyl]-piperidin-4-one (0.10 g, 0.31 mmol) in dichloromethane (2 mL) was added azepane (0.05 mL, 0.46 mmol). After 30 min stirring at room temperature a drop of acetic acid was added, and after 1 h a further aliquot of azepane (0.05 mL, 0.46 mmol) was added, followed by sodium triacetoxyborohydride (NaB(OAc)3H) (0.10 g, 0.46 mmol). The reaction mixture was stirred at room temperature overnight, then the solvent was removed under reduced pressure, and the crude product dissolved in dichloromethane (10 mL). To the solution PS-isocyanate resin (PS-NCO) (Argonaut, loading 0.93 mmol/g) was added, then the mixture was shaken at room temperature overnight and filtered. The solvent was removed under reduced pressure to obtain a solid residue that was washed with EtOAc and Et2O then dried to give the desired product (0.07 g, 58%).
