反应详情

A solution of benzyl 3-oxopyrrolidine-1-carboxylate (11.2 g, 51.09 mmol), ethylene glycol (2.4 g, 38.67 mmol) and TsOH.H2O (10 mg) in benzene (100 mL) was heated at reflux using Dean-Stork condenser. After 20 h, the reaction mixture was cooled, diluted with EtOAc (100 mL), washed with water (2×25 mL), brine (25 mL), dried (MgSO4), filtered and concentrated to give yellow oil. Flash column chromatography purification on silica gel column with 1:4 followed by 3:7 EtOAc:hexanes provided desired product (10.32 g, 100%) as colorless liquid. 1H NMR (500 MHz, CDCl3) δ: 7.38-7.28 (5H, m), 5.13 (2H, s), 3.99-3.92 (4H, m), 3.58-3.54 (2H, m), 3.45 (2H, d, J=10.7 Hz), 2.07-2.02 (2H, m).

1. temperatureat reflux
2. temperaturethe reaction mixture was cooled
3. washwashed with water (2×25 mL), brine (25 mL)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated
7. customto give yellow oil
8. customFlash column chromatography purification on silica gel column with 1:4