tert-Butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate

Under argon atmosphere, wet Pd/C (188.05 mg, 159.50 μmol, purity 10%) was added into tert-butyl 9-benzyl-3,9-diazaspiro[5.5]undecane-3-carboxylate in THF solution (1.10 g, 3.19 mmol), after replacing the gas in the flask 3 times with hydrogen, the reaction was stirred at 40°C for 40 hours under 45 Psi. After completion of the reaction, the solution was filtered through diatomite. The filtrate was concentrated to give the crude tert-Butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate.