Hydrochloric Acid → 2,3-Dichlorobenzeneboronic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 1-bromo-2,3-dichlorobenzene (20 g, 0.088 mole, Aldrich) in dry tetrahydrofuran (44.24 ml) was added dropwise to a solution of n-butyllithium (1.6M in hexane, 66.36 ml, 0.11 mole) in anhydrous tetrahydrofuran (16 ml), maintaining the temperature below −65° C. The resulting pale yellow suspension was stirred at −78° C. for 75 min. Trimethylborate (13.28 ml, 12.16 g, 0.12 mole) was added dropwise maintaining the temperature below −55° C. The resulting pale yellow solution was warmed to room temperature overnight. Excess n-butyllithium was decomposed with water (30 ml) and the reaction mixture was evaporated in vacuo. The residue obtained was suspended in water and acidified with 2M hydrochloric acid (10 ml). The insoluble solid was filtered, washed well with water and dried. The solid was suspended in 60-80° C. petroleum ether, stirred at room temperature for 10 min, filtered dried in vacuo. Yield 8.42 g (50%), M.p. 235-238° C.

Provenance & Evidence