A mixture of 3.30 g (13.1 mmol) of 5-hexylthiophen-2-ylhydroxyboronic acid sodium salt, 4.20 g (13.1 mmol) of 4-bromo-2-fluoro-4′-pentylbiphenyl, 2.2 g (26.2 mmol) of sodium hydrogencarbonate and 0.70 g (0.61 mmol) of tetrakis(triphenylphosphine)palladium(0) in THF/water (1:1) is refluxed for 6 h. The mixture is diluted with MTBE, and the organic phase is separated off. The aqueous phase is extracted with MTBE. The combined organic phases are washed with sat. sodium chloride solution and dried using sodium sulfate. The solution is evaporated to dryness, and the residue is purified by column chromatography (SiO2, n-heptane). The further purification is carried out by recrystallisation from methanol/-pentane (5:1). 2-(2-Fluoro-4′-pentylbiphenyl-4-yl)-5-hexylthiophene is obtained as a colourless solid having an m.p. of 44° C.
