反应详情

To a 500 mL round bottom flask equipped with a reflux condenser were added 2-bromobenzaldehyde (102.5 g, 0.554 mol, Aldrich), trimethyl orthoformate (64.9 mL, 0.594 mol, Aldrich), 10-camphor sulfonic acid (1.25 g, 5.40 mmol, Aldrich), and methanol (100 mL). The reaction was heated at reflux for 14 hrs and concentrated in vacuo. The residue was taken up in 500 mL of ether, washed with 200 mL each of sat. aqueous sodium bicarbonate, water, and sat. aqueous NaCl, dryed over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was distilled through a 27 cm Vigrew column (b.p. 78-82° C./1.2 mmHg), affording a clear colorless oil (120.8 g, 94%). 1H-NMR (300 MHz, CDCl3) δ3.37 (s, 6H), 5.54 (s, 1H), 7.18 (dt, 1H, J=1.7, 8.1 Hz), 7.31 (dt, 1H, J=1.2, 7.5 Hz), 7.54 (dd, 1H, J=1.2, 8.1 Hz), 7.59 (dd, 1H, J=1.7, 7.5 Hz). Mass spectrum (EI+) m/e 230, 232 (M+), 199, 201 (bp).

1. customTo a 500 mL round bottom flask equipped with a reflux condenser
2. temperatureThe reaction was heated
3. temperatureat reflux for 14 hrs
4. concentrationconcentrated in vacuo
5. washwashed with 200 mL each of sat. aqueous sodium bicarbonate, water, and sat. aqueous NaCl
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. distillationThe crude product was distilled through a 27 cm Vigrew column (b.p. 78-82° C./1.2 mmHg)