Methyl 4-hydroxy-3-[(trimethylsilyl)ethynyl]benzoate → Methyl 1-benzofuran-5-carboxylate
反応式
[OH:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][C:3]=1[C:12]#[C:13][Si](C)(C)C>CO>[O:1]1[C:2]2[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][C:3]=2[CH:12]=[CH:13]1参加物
3
反応条件
- 温度
- 60 °C
実験手順
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.