反应详情

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).

1. temperaturethen cooled to −10 C
2. customThe mixture was slowly quenched with aqueous 1N hydrochloric acid until it
3. additionThe mixture was diluted with dichloromethane
4. washwashed with water (2×) and brine
5. dry with materialThe organic layer was dried over sodium sulfate
6. concentrationconcentrated in vacuo
7. customThe remaining orange-brown solid was purified by silica gel chromatography (1:4 EtOAc/hexane)