Chloride → 5-fluoro-2,2,7-trimethylbenzofuran-3(2H)-one

Participants

Reaction Steps

To a solution of 2-(4-fluoro-2-methylphenoxy)-2-methylpropanoic acid (658) (5 g, 23.6 mmol) in tetrahydrofuran (50 mL) at 0° C. was added cat. DMF and oxayl chloride (2.5 mL, 28.3 mmol). The reaction was warmed to room temperature, stirred for 1 hour, and concentrated in vacuo. The oil was dissolved in dichloromethane (50 mL), cooled to −78° C. and AlCl3 (7.6 g, 56.6 mmol) was added. The reaction was allowed to warm to room temperature overnight. Ice water was added and the dichloromethane was removed in vacuo. The aqueous phase was extracted with ethyl acetate (3×50 mL) and washed with saturated sodium bicarbonate dried over sodium sulfate, filtered and concentrated in vacuo. The crude compound was purified by flash column chromatography on silica gel with hexanes and EtOAc (20%) to provide 5-fluoro-2,2,7-trimethylbenzofuran-3(2H)-one (659).

Provenance & Evidence