Boron trifluoride → 6-Methoxy-1-benzothiophene

Participants

Reaction Steps

To the obtained (2,2-diethoxyethyl)(3-methoxyphenyl)sulfane (91, 3.6 g, 14.0 mmol) dissolved in a dichloromethane solution (70 mL) was slowly added trifluoroborane etherate (BF3-Et2O; 1.75 mL, 13.72 mmol) at room temperature under nitrogen, and the reaction mixture was stirred for one hour and neutralized with a sodium bicarbonate solution at room temperature. Organic layer was isolated, organic compounds in water were extracted with dichloromethane, the recovered organic solution was evaporated after a treatment with sodium sulfate, and concentrated under reduced pressure. After concentration, residues were purified by column chromatography to give the target compounds 4-methoxybenzothiophene (92a, 368 mg, 16%) and 6-methoxybenzothiophene compounds (92b, 1.38 g, 60%) as transparent liquids.

Provenance & Evidence