反应详情

Magnesium turnings (9.64 g, 397 mmol) were heated to 160° C. under vacuum for 2 hours, then were cooled to RT under nitrogen. THF (400 mL) was added followed by portionwise addition of 4-bromobenzaldehyde diethyl acetal (80.0 mL, 393 mmol). The mixture was heated with a heat gun to initiate the reaction, then allowed to stir at RT (while gently refluxing) for 90 min. The resulting dark red solution was cooled to 0° C. and a solution of 2 (77.27 g, 304 mmol) in THF (50 mL) was added. The mixture was stirred at RT for 3 hours. Saturated aqueous NH4Cl (150 mL) and H2O (150 mL) were added and the two layers were separated. The aqueous layer was extracted with Et2O (3×100 mL), and the combined organics were dried (MgSO4) and concentrated to provide 3 as a light yellow oil that was carried on without further purification. 1H NMR (400 MHz, CDCl3): δ 0.72 (t, J=7.3 Hz, 3H), 1.25 (t, J=7.0 Hz, 6H), 1.77 (q, J=7.3 Hz, 2H), 2.35 (s, 1H), 3.69 (s, 3H), 3.52-3.65 (m, 5H), 5.50 (s, 1H), 6.62 (d, J=8.8 Hz, 2H), 7.08 (m, 1H), 7.12 (m, 6H), 7.44 (d, J=8.2 Hz, 2H), 7.53 (d, J=8.2 Hz, 2H).

1. temperatureThe mixture was heated with a heat gun
2. customthe reaction
3. temperaturewhile gently refluxing) for 90 min
4. temperatureThe resulting dark red solution was cooled to 0° C.
5. stirringThe mixture was stirred at RT for 3 hours
6. customthe two layers were separated
7. extractionThe aqueous layer was extracted with Et2O (3×100 mL)
8. dry with materialthe combined organics were dried (MgSO4)
9. concentrationconcentrated