Trimethyl borate → HCID 66953917, compound

Participants

Reaction Conditions

Reaction Steps

1-Fluoro-2,3-methylenedioxybenzene (5.0 g, 35.7 mmol) was dissolved in THF (70 mL) and the solution cooled to −65° C. in a dry ice acetone bath. n-Butyl lithium (2.5 g, 15.7 mL, 39.3 mmol) was added to the solution via syringe with stirring. The reaction was allowed to warm to −35° C. over 1 hour then re-cooled to −65° C. and treated with trimethylborate (4.1 g, 39.3 mmol) via syringe. The reaction was allowed to warm slowly to room temperature then quenched with 1N HCl (50 mL), stirred for 15 minutes then diluted with ether and the layers separated. The organic layer was extracted with 1N sodium hydroxide and this extract separated from the ether and acidified with 1N hydrochloric acid. The acidic aqueous layer was extracted with two portions of ether and these combined ether extracts were dried (sodium sulfate), filtered and concentrated to a oily solid which was triturated with methylene dichloride. The resulting solid was collected by filtration, washed with methylene dichloride and dried to give 1-fluoro-2,3-methylenedioxyphenylboronic acid (1.4 g, 7.6 mmol) as a tan solid: 1H NMR (DMSO-d6): δ 8.05 (bs, 2H), 7.08 (dd, 1H), 6.76 (d, 1H), 6.08 (s, 2H).

Provenance & Evidence