反应详情

2-(tert-Butoxycarbonylamino)-2-cyclopropylacetic acid (13) (5.47 g, 25.4 mmol), Meldrum's acid (14) (4.02 g, 27.9 mmol), and DMAP (4.34 g, 35.56 mmol) were added to CH2Cl2 (100 mL) under nitrogen at 0° C. After 30 minutes EDAC (6.81 g, 35.56 mmol) was added. The reaction was stirred 16 hr at rt and poured into EtOAc (300 mL), washed with brine (200 ml), 5% citric acid (300 mL), and again brine (200 mL). The organic phase was then refluxed for 1 hr. The mixture was evaporated to give (S)-tert-butyl 2-cyclopropyl-3,5-dioxopyrrolidine-1-carboxylate (15) a yellow oil (4.0 g, 69%) that was taken into the next reaction without further purification.

1. washwashed with brine (200 ml), 5% citric acid (300 mL), and again brine (200 mL)
2. temperatureThe organic phase was then refluxed for 1 hr
3. customThe mixture was evaporated