A mixture of 56.0 g (0.27 mol) of 2-bromoselenophene, 70.0 g (0.27 mol) of 2,3-difluoro-4′-ethylbiphenyl-4-ylboronic acid, 22.0 g (19.0 mmol) of tetrakis(triphenylphosphine)palladium(0) and 800 ml of 2 N sodium carbonate soln. in 2.5 l of toluene/ethanol (1:1) is heated at 90° C. for 17 h. After cooling, the organic phase is separated off, and the aqueous phase is extracted with toluene. The combined organic phases are washed with water, and the solution is dried using sodium sulfate. The solution is concentrated to dryness, and the residue is purified by column chromatography (SiO2, toluene). The further purification is carried out by recrystallisation from ethanol and n-heptane. 2-(4′-Ethyl-2,3-difluorobiphenyl-4-yl)-selenophene is obtained as a yellowish solid.
