Hydrochloric Acid → 2-Chloro-4-methoxybenzeneboronic acid

Beteiligte Stoffe

Reaktionsschritte

Part I. A solution of the iodide compound from Part H(7.00 g, 26.1 mmol) in anhydrous tetrahydrofuran (50 mL) was cooled to −90° C., and treated with a hexane solution of n-butyllithium (16.5 mL, 1.6 M, 26.4 mmol). After 15 minutes, the solution was treated with triisopropylborate (6.10 mL, 26.4 mmol) and was allowed to warm to ambient temperature over 6 hours. The resulting mixture was treated with 6 N aqueous HCl (5 mL) and water (5 mL), which was stirred for 1 hour, then poured into water (100 mL) and extracted with ethyl acetate (2×100 mL). The extracts were washed in sequence with 1 N aqueous sodium bisulfite and brine (80 mL each), combined, dried over sodium sulfate, filtered and evaporated. The residual solid was triturated with 1:1 ether-hexane, collected by filtration and dried under vacuum to afford pure product, 2-chloro-4-methoxybenzeneboronic acid (3.05 g, 16.4 mmol, 63%). m.p. 191-195° C.

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