Hydrochloric Acid → 1-Chloro-4-fluoro-2-iodo-5-methoxyphenyl boronic acid

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Reaction Steps

To 1-chloro-4-fluoro-2-iodo-5-methoxy-benzene (10.0 g, 34.9 mmol) in THF (70 mL) was cooled to −78° C. was added triisopropylborate (8.9 mL, 38.4 mmol) followed by dropwise addition of n-butyl lithium (24 mL of a 1.6 M solution in hexanes, 38.4 mL). The solution was stirred and allowed to warm to room temperature over night by dissipation of the dry ice/acetone bath. 1N HCl (50 mL0 and water (50 mL) were added and the solution stirred at room temperature for 1 h. The solution was extracted with ethyl acetate. The organic layers were washed with brine, dried (Na2SO4), filtered and concentrated in vacuo. The residue was triturated with 1:1 hexanes/diethyl ether and the solid collected by filtration to give 3.8 g (53%) of pure 1-chloro-4-fluoro-2-iodo-5-methoxyphenyl boronic acid: 1H NMR (400 MHz, CDCl3): δ 7.64 (d, J=11.7 Hz, 1H), 6.91 (d, J=7.3 Hz, 1H), 5.21 (br s, 2H), 3.90 (s, 3H).

Provenance & Evidence