Acetic Anhydride → 2-Methylbenzofuran-6-yl acetate

Participants

Reaction Conditions

Reaction Steps

A solution of 6-methoxy-2-methyl-benzofuran (17.4 g, 107 mmol) in dichloromethane (200 mL) at 0° C. is treated with boron tribromide (1.0 M, 107 mL). The mixture is stirred at 0° C. for 60 minutes and quenched with water (50 mL). The organic layer is dried over Na2SO4, filtered, and concentrated. The crude product is purified by flash chromatography eluted with 25% EtOAc/Hexanes, and the appropriate fractions are concentrated. The material is dissolved in dichloromethane (150 mL) and triethylamine (17.0 mL, 122 mmol) at 0° C. is treated with acetic acid anhydride (7.22 mL, 76.35 mmol). The reaction is stirred for 16 hours and allowed to warm to room temperature. The reaction is quenched with MeOH (10 mL) and concentrated. The residue is purified by silica gel chromatography with 25% EtOAc/Hexanes to provide acetic acid 2-methyl-benzofuran-6-yl ester (9.50 g, 82%). 1H NMR (400 MHz, CDCl3): δ 7.40-7.38 (d, 1H), 7.15 (s, 1H), 6.91-6.88 (d, 1H), 6.32 (s, 1H), 2.41 (s, 3H), 2.29 (s, 3H).

Provenance & Evidence