Boron tribromide → Methyl 6-hydroxybenzofuran-3-carboxylate
反応式
C[O:2][C:3]1[CH:15]=[CH:14][C:6]2[C:7]([C:10]([O:12][CH3:13])=[O:11])=[CH:8][O:9][C:5]=2[CH:4]=1.B(Br)(Br)Br>ClCCl>[OH:2][C:3]1[CH:15]=[CH:14][C:6]2[C:7]([C:10]([O:12][CH3:13])=[O:11])=[CH:8][O:9][C:5]=2[CH:4]=1参加物
4
実験手順
Methyl 6-methoxybenzofuran-3-carboxylate (498 mg, 2.42 mmol) was dissolved in dichloromethane (100 mL) then cooled to −10 C. A solution of 1M boron tribromide in dichloromethane (9.67 mL, 9.67 mmol) was added slowly via syringe. The dark purple reaction mixture was warmed to RT over 3 h then continued stirring at RT for an additional 4 h. The mixture was slowly quenched with aqueous 1N hydrochloric acid until it became colorless. The mixture was diluted with dichloromethane and washed with water (2×) and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo. The remaining orange-brown solid was purified by silica gel chromatography (1:4 EtOAc/hexane) to afford methyl 6-hydroxybenzofuran-3-carboxylate as an off-white solid. MS (ESI, neg. ion) m/z: 191.1 (M−1).