A mixture of 25.3 g (0.16 mol) of 2-bromothiophene, 40.0 g (0.16 mol) of 4′-propyl-3-fluoro-4-biphenylboronic acid, 8.5 g (7.4 mmol) of tetrakis(triphenylphosphine)palladium(0) and 170 ml of 2 N sodium carbonate solution in 420 ml of toluene/ethanol (1:2) is refluxed for 18 h. After cooling, the organic phase is separated off, and the aqueous phase is extracted a number of times with toluene. The combined organic phases are washed with water and sat. sodium chloride solution. The solution is dried using sodium sulfate and evaporated to dryness. The residue is purified by column chromatography (SiO2, n-heptane:toluene=9:1). The further purification is carried out by recrystallisation from ethanol and n-heptane, giving 2-(4′-propyl-3-fluorobiphenyl-4-yl)thiophene as a colourless solid (m.p. 88° C.).
