反应详情

To a solution of (S,S)-2,5-diaza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (35.6 g, 179 mmol) in CH2Cl2 (600 mL) was added trimethylsilylisocyanate (82.5 g, 716 mmol). After 2 h at rt, the mixture was concentrated, and the resulting white solid was dissolved in CH2Cl2 (500 mL). The solution was then treated with a solution of HCl (4.0 N in 1,4-dioxane, 135 mL). The resulting heterogeneous suspension was then stirred at rt overnight. Upon evaporation of the solvents, the desired product was isolated as a white solid (33 g), which was used directly in the next step. [Note: the mass balance was found to be 104%, which arose from additional HCl that could not be removed by standard evaporation under vacuum]. 1H NMR (500 MHz, CD3OD): 4.77 (s, 1H), 4.55 (s, 1H), 3.69 (d, J=12.1 Hz, 1H), 3.64 (d, J=12.1 Hz, 1H), 3.47 (d, J=11.3 Hz, 1H), 3.40 (d, J=11.3 Hz, 1H), 2.22 (d, J=11.5 Hz, 1H), 2.15 (d, J=11.5 Hz, 1H).

1. concentrationthe mixture was concentrated
2. dissolutionthe resulting white solid was dissolved in CH2Cl2 (500 mL)
3. additionThe solution was then treated with a solution of HCl (4.0 N in 1,4-dioxane, 135 mL)
4. customUpon evaporation of the solvents