Ethylenediaminetetraacetic Acid → 2-Fluoro-5-(trifluoromethoxy)benzeneboronic acid

Beteiligte Stoffe

Reaktionsschritte

To a solution of the 4-fluoro(trifluoromethoxy)benzene (2.0 g, 11.1 mmol) in dry THF (30 ml) at −78° C., was added ethylenediaminetetraacetic acid (EDTA, 1.36 g, 11.7 mmol) followed by a 1.4 M solution of sec-butyllithium in cyclohexane (8.33 ml, 11.7 mmol) and the reaction stirred for 2 hours under nitrogen. To this reaction mixture at −78° C., was then added dropwise the preformed dimethoxyfluoroborane mixture. The reaction was stirred at −78° C. for 30 minutes, warmed to room temperature for 30 minutes, and then quenched with water (10 ml). The volume of the reaction mixture was reduced in vacuo, then the residue dissolved in diethyl ether (10 ml) and washed with an aqueous solution of 10% NaOH (50 ml). The aqueous layer was acidified and extracted with ethyl acetate (3×40 ml). The combined ethyl acetate extracts were dried over MgSO4 and concentrated in vacuo to afford the title compound as a single regioisomer (1.51 g).

Herkunft & Nachweise