反应详情

4-Pentenoic acid (12.0 g, 0.120 mol) was dissolved in 200 ml of dry EtOH and KOH pellets (7.1 g, 0.126 mol) were added. The mixture was stirred at room temperature until homogeneous. Ethyl iodide (24.3 g, 0.156 mol) was added and the solution was refluxed for 48 hrs. The cooled solution was poured onto H2O (600 ml) and extracted with pentane (200 ml). The organic extract was washed with H2O (2×500 ml) and dried (MgSO4). Solvent removal afforded 10.0 g (65%) of ethyl 4-pentenoate. From the ethyl 4-pentenoate the corresponding epoxy ester, ethyl 4,5-epoxy-pentanoate, is prepared as follows: ethyl 4-pentenoate (9.90 g, 77.3 mmol), and m-chloroperbenzoic acid (18.5 g, 92.8 mmol, 85% assay) were dissolved in 300 ml of CH2Cl2 and stirred for 18 hr in an oil bath at 50° C. The mixture was then filtered, washed with 10% NaHSO3, saturated aqueous NaHCO3 (2X), and H2O (2X) before drying (MgSO4). Concentration under slight vacuum at room temperature followed by distillation (32° C., 0.07 mm) afforded 6.1 g (55%) of the ethyl 4,5-epoxy-pentanoate.

1. temperaturethe solution was refluxed for 48 hrs
2. additionThe cooled solution was poured onto H2O (600 ml)
3. extractionextracted with pentane (200 ml)
4. extractionThe organic extract
5. washwas washed with H2O (2×500 ml)
6. dry with materialdried (MgSO4)
7. customSolvent removal