To a solution of (S)-tert-butyl 6-(aminomethyl)-5-azaspiro[2.4]heptane-5-carboxylate (prepared according to WO2011006960; 136 mg, 0.6 mmol) in acetonitrile (1.5 ml), DIPEA (156 μl, 0.9 mmol) and benzylchloroformate (100 μl, 0.7 mmol) were added. After 1 h at RT the reaction was diluted with DCM (20 ml) and washed with an aqueous satd. solution of NH4Cl; organics were evaporated to obtain an oil, which was purified on silica gel column (Cyclohexane/AcOEt from 9/1 to 7/3). Yield 168 mg, transparent oil.
