Phosphorus tribromide → 2-Bromomethyl-5-chloro-4-methoxy-3-methyl benzofuran

Participants

Reaction Steps

To a 0° C. solution of (5-chloro-4-methoxy-3-methyl benzofuran-2-yl)-methanol (0.29 g; 1.3 mmol) in dichloromethane (5 mL) was added neat phosphorus tribromide (0.18 mL; 0.52 g; 1.9 mmol; 1.5 eq) and pyridine (3 drops). The ice bath was removed and the reaction was allowed to warm to room temperature overnight. Additional phosphorus tribromide (0.09 mL; 0.26 g; 0.95 mmol; 0.75 eq) was added and stirring continued at room temperature. After two hours, the reaction was quenched with ice and extracted twice with ethyl acetate. The combined organic layers were washed with water and saturated sodium bicarbonate, followed by drying over magnesium sulfate, filtration and concentration in vacuo to give essentially pure 2-bromomethyl-5-chloro-4-methoxy-3-methyl benzofuran (0.37 g; 99%).

Provenance & Evidence