Tetrafluoroboric acid → 1-tert-Butyl-3-fluorobenzene

Participants

Reaction Steps

To a vigorously stirred solution of tetrafluoroboric acid (73.26 mL; 0.4 mol; 48% wt % solution in water) in a large beaker at room temperature was slowly added 3-tert-butylaniline (15.0 g; 0.10 mmol). The resulting mixture was stirred at room temperature for 30 minutes, cooled to 0° C. and then a solution of sodium nitrite (11.09 g; 0.16 mol) in water (30 mL) was added. After addition was complete reaction mixture was stirred at 0° C. for 30 minutes, warmed to room temperature and further stirred for 20 minutes. The resulting beige slushy material was filtered, washed with tetrafluoroboric acid (20 mL) and ether (3×20 mL) to yield an off-white solid (13.54 g). The latter was dissolved in dichloromethane (300 mL) and heated at reflux for 2 hours until the solid was dissolved and no more gas (HF) evolution was observed. The reaction mixture was cooled to room temperature and concentrated under reduced pressure to yield a dark oil that was purified by column chromatography eluting with ethyl acetate/hexanes (0 to 5% v/v gradient elution over 1 L) to yield the title compound as a pale yellow liquid (11.80 g).

Provenance & Evidence