tert-Butyl 3,6-diazabicyclo[3.1.1]heptane-6-carboxylate

To a stirred solution of 3,6-Diazabicyclo[3.1.1]heptane-6-carboxylic acid, 3-[(2-nitrophenyl)sulfonyl]-, 1,1-dimethylethyl ester (400 mg, 1.04 mmol) in DMF (2.5 mL) were added dodecanethiol (500 μL, 2.09 mmol) and lithium hydroxide hydrate (88 mg, 2.09 mmol). The mixture was stirred at r.t. for 2 h. The mixture was diluted with hexanes-ethyl acetate (10 mL, 1:1). The mixture was extracted with aq. Hydrochloric acid (2 x 5.0 mL). The aq. layer was extracted with hexanes-ethyl acetate (10 mL, 1:1). The combined organic layers were discarded. The aq. layer was basified with NaOH (6.0 mL of 1.0 M solution) until pH=13. The aq. layer was extracted with methylene chloride-methanol (2 x 10 mL, 9:1). The organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to afford tert-Butyl 3,6-diazabicyclo[3.1.1]heptane-6-carboxylate as a white solid; Yield, 167 mg (81percent)