(Diethylamino)sulfur trifluoride → 1-Bromo-4-chloro-2-(fluoromethyl)benzene

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Reaction Steps

To a suspension of 2-bromo-5-chlorobenzyl alcohol (2.0 g, 9.0 mmol, Fluorochem) in anhydrous DCM (30 mL) was added (diethylamino)sulfur trifluoride (1.30 mL, 10 mmol), at about −75° C. After complete addition the mixture was allowed to warm slowly to rt, over about 1 h. Then saturated aqueous sodium bicarbonate (8 mL) was added and the mixture was partitioned between DCM (20 mL) and water (20 mL). The layers were separated and the aqueous layer was extracted twice with DCM (20 mL). The combined organic layers were washed with brine (20 mL), dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by column chromatography (SiO2, DCM/hexanes 1:1) to give 1-bromo-4-chloro-2-(fluoromethyl)benzene (1.31 g, 5.9 mmol, 65%) as a pale yellow oil: 1H-NMR (CDCl3, Bruker 400 MHz) δ 5.42 (2 H, d, J=47.0 Hz) 7.19 (1 H, dd, J=8.8, 2.5 Hz) 7.41 (1 H, d, J=2.5 Hz) 7.48 (1 H, d, J=8.8 Hz).

Provenance & Evidence