1034305-11-7

93777-26-5

95-15-8

1034305-11-7

At -78 °C, 16.6 g (124 mmol) of benzothiophene was dissolved in 200 mL of tetrahydrofuran. 78.5 mL (937 mmol) of n-butyllithium was slowly added, keeping the reaction temperature at -78 °C with continuous stirring for 1.5 hours. Subsequently, 23.95 g (118 mmol) of 5-bromo-2-fluorobenzaldehyde was dissolved in 300 mL of tetrahydrofuran and this solution was added drop-wise to the above benzothiophene solution and stirring was continued at -78 °C for 2 hours. Upon completion of the reaction, water and ether were added to the mixture for extraction. The organic phase was separated, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (eluent: ethyl acetate/hexane mixed solvent) to afford the target product benzo[b]thiophen-2-yl(5-bromo-2-fluorophenyl)methanol 35.4 g, with 99.5% purity and 89% yield.