Hydrogen Peroxide → 8-Fluoro-2,3-dihydro-1,4-benzodioxin-6-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of 7-bromo-5-fluoro-2,3-dihydrobenzo[b][1,4]dioxine (15.1 g, 64.8 mmol) in tetrahydrofuran (160 mL) at −78° C. was added a 1.6 M solution of n-butyllithium in hexanes (45 mL, 73 mmol). The reaction mixture was stirred at −78° C. for 15 min and trimethyl borate (8.5 g, 82 mmol) was added. The reaction mixture was allowed to warm to ambient temperature, stirred for 48 h and cooled to 5° C. 35% w/w aqueous hydrogen peroxide (12.6 mL, 129.6 mmol) was added, the reaction mixture was allowed to warm to ambient temperature and stirred for 3 h. The reaction mixture was diluted with ethyl acetate (200 mL) and the organic phase was washed with 1 M hydrochloric acid (50 mL) and brine (50 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification of the residue by column chromatography eluted with a 0% to 70% gradient of ethyl acetate in hexanes afforded 8-fluoro-2,3-dihydrobenzo[b][1,4]dioxin-6-ol (6.5 g, 59%) as a colorless solid: MS (ES+) m/z 153.0 (M−17).

Provenance & Evidence