反应详情

To a stirred solution of ethyl 3-oxocyclobutanecarboxylate (2 g, 14.07 mmol) in dry Et2O (30 mL), cooled to −80° C., was added 4-fluorophenyl magnesium bromide (16.88 mL, 16.88 mmol, 1 M in THF) dropwise. The reaction mixture was then allowed to warm to RT and stir for an additional 2 h. The reaction mixture was quenched with a saturated aq. solution of NH4Cl (50 mL) and extracted with EtOAc (3×30 mL). The combined organic layer was washed with brine, dried over Na2SO4, filtered and concentrated. The crude reaction mixture was purified by silica gel chromatography (24 g REDISEP® column, eluting with 15% EtOAc in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate 276A as a colorless liquid (1.7 g, 51%). 1H NMR (400 MHz, DMSO-d6) δ ppm 7.54 (dd, J=5.5, 9.0 Hz, 2H), 7.15 (t, J=8.8 Hz, 2H), 4.09 (q, J=7.4 Hz, 2H), 2.83-2.71 (m, 1H), 2.61 (s, 2H), 2.55-2.51 (m, 2H), 1.24-1.12 (t, 3H).

1. customThe reaction mixture was quenched with a saturated aq. solution of NH4Cl (50 mL)
2. extractionextracted with EtOAc (3×30 mL)
3. washThe combined organic layer was washed with brine
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated
7. customThe crude reaction mixture
8. customwas purified by silica gel chromatography (24 g REDISEP® column, eluting with 15% EtOAc in hexanes)
9. additionFractions containing the product
10. customevaporated