反应详情

To a solution of ethyl 4-oxopentanoate (4.92 mL, 34.7 mmol) in Et2O (180 mL) at about 0° C. was added bromine (1.8 mL, 34.7 mmol) in Et2O (10 mL) and the reaction was stirred for about 3 h. To the reaction mixture was added saturated aqueous sodium thiosulfate (50 mL) and stirred for about 10 min. The reaction was warmed to ambient temperature. The organic layer was separated and the aqueous layer was back extracted with Et2O (30 mL). The combined organic layers were washed with water (20 mL), dried over MgSO4, filtered and concentrated under reduced pressure. The resulting oil was purified by column chromatography (SiO2, EtOAc/heptane 100:0 to 0:20) to afford ethyl 3-bromo-4-oxopentanoate (3.29 g, 14.6 mmol, 43%). 1H NMR (CDCl3) δ 4.67-4.33 (m, 1H), 4.15 (q, J=7.1 Hz, 2H), 3.29-3.22 (m, 1H), 2.90-2.86 (m, 1H), 2.42 (s, 3H), 1.26 (t, J=7.1 Hz, 3H).

1. stirringstirred for about 10 min
2. customThe organic layer was separated
3. extractionthe aqueous layer was back extracted with Et2O (30 mL)
4. washThe combined organic layers were washed with water (20 mL)
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe resulting oil was purified by column chromatography (SiO2, EtOAc/heptane 100:0 to 0:20)