反应详情

温度

-78 °C

To a solution of LDA (146 ml, 291 mmol, 2M in THF) at −78° C. under nitrogen was added a solution of ethyl isobutyrate (33.9 g, 291 mmol) in dry THF (100 ml) and the mixture was stirred at −78° C. for 2 hours. To the mixture was added 2-pentynyl chloride (25 g, 243 mmol) slowly over a period of 20 min. The reaction mixture was slowly warmed to RT over a period of 12 hours. Water (200 ml) was added and the product was extracted with Et2O (2×200 ml). The combined organic layers were washed with water, brine and dried (MgSO4). The solvent was removed under vacuum and the residue was purified by flash chromatography on silica (pet. ether/EtOAc 9/1) to afford the titled compound as a colorless liquid (29 g, 66%). TLC: Pet ether/EtOAc (8/2): Rf=0.75. 1H-NMR (CDCl3:300 MHz) δ 1.11 (3H, t), 1.24 (6H, s), 2.15 (2H, m), 2.38 (2H, s), 4.14 (2H, m).

1. temperatureThe reaction mixture was slowly warmed to RT over a period of 12 hours
2. extractionthe product was extracted with Et2O (2×200 ml)
3. washThe combined organic layers were washed with water, brine
4. dry with materialdried (MgSO4)
5. customThe solvent was removed under vacuum
6. customthe residue was purified by flash chromatography on silica (pet. ether/EtOAc 9/1)