Sodium Hydroxide → 2-Bromo-1-chloro-3-fluorobenzene

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Reaction Steps

A solution of 261.1 g (2.0 mol) of 1-chloro-3-fluorobenzene in 2000 ml of dry tetrahydrofuran under nitrogen is cooled to −78°. To the solution is added 960 ml (2.4 mol) of 2.5 M n-butyllithium in hexanes over a period of 40 minutes. After stirring for 2.5 hours, a slurry of 155 ml of bromine cooled to −78° is added over 30 minutes and the mixture is stirred for 40 minutes before warming to −10°. The reaction is quenched with an aqueous solution of 151.3 g (1.2 mol) of sodium sulfite and 16.0 g (0.4 mol) of sodium hydroxide in 500 ml of water. The organic layer is separated, the solvents are removed at ambient pressure, and the product is distilled at 92-96° (20 mm Hg) to obtain 2-bromo-3-fluoro-chlorobenzene as a colorless oil.

Provenance & Evidence