反应详情

温度

60 °C

Methyl 4-hydroxy-3-[(trimethylsilyl)ethynyl]benzoate (11 g, 44.5 mmol) is combined with DIA (7.1 ml, 50 mmol) and cuprous iodide (423 mg, 2.2 mmol) in 100 ml MeOH in a flask under nitrogen. The reaction is warmed to 60° C. for 6 h, the volatiles are removed in vacuo, and the brown-green residue is chromatographed over 500 g silica gel (230-400 mesh) eluting with 20% EtOAc/hexane. The appropriate fractions are combined and concentrated to give 2.63 g (34%) of methyl benzofuran-5-carboxylate as a pale oil which crystallized on standing. 1H NMR (300 MHz, CDCl3): δ 3.95, 6.86, 7.53, 7.70, 8.03, 8.36 ppm.

1. customthe volatiles are removed in vacuo
2. customthe brown-green residue is chromatographed over 500 g silica gel (230-400 mesh)
3. washeluting with 20% EtOAc/hexane
4. concentrationconcentrated