146231-54-1

24424-99-5

96896-09-2

146231-54-1

Cis-hexahydrocyclopentadieno[c]pyrrol-5(1H)-one (2.0 g, 16 mmol) was used as starting material and dissolved in dichloromethane (50 mL). Subsequently, di-tert-butyl dicarbonate (5.2 g, 24 mmol), triethylamine (3.2 g, 32 mmol) and 4-dimethylaminopyridine (195 mg, 1.6 mmol) were added to the solution. The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, it was quenched by adding water (100 mL) and the aqueous and organic phases were separated. The organic phase was dried with anhydrous sodium sulfate, filtered and concentrated to give the crude product. The crude product was purified by silica gel column chromatography (eluent ratio of petroleum ether:ethyl acetate=10:1) to finally obtain tert-butyl cis-5-oxooctahydrocyclopenta[c]pyrrole-2(1H)-carboxylate (3.4 g, 94.4% yield).