3-Bromo-2,2′-bithiophene (IIIa) (5.00 g, 20 mmol) in dry diethylether (170 mL) was added slowly to a solution of n-butyllithium (1.6 M in hexane, 12.5 mL, 20 mmol) in dry diethylether (170 mL) at −78° C. over 2 h under N2. The mixture was stirred for 15 minutes at the same temperature. Heptadecan-9-one (6.22 g, 24 mmol) was added to the mixture at −78° C., followed by stirring overnight at room temperature. The reaction was quenched with an aqueous NH4Cl-solution (2.5 M, 85 mL) and water (85 mL) at 0° C. The organic phase was separated and the aqueous phase was extracted with diethylether. The combined organic phases were washed with brine, dried over MgSO4 and evaporated under reduced pressure to give a crude oil. The oily residue was purified by gradient column chromatography (eluent hexane/EtOAc 95:5) to afford the title compound (IIe) as a yellow oil (6.3 g, 75%). 1H-NMR (CDCl3): δ=7.34 (dd, J=5.1 Hz, J=1.3 Hz, 1H), 7.22 (d, J=5.3 Hz, 1H), 7.07 (dd, J=3.5 Hz, J=1.2 Hz, 1H), 6.99 (dd, J=5.1, J=3.5 Hz, 1H), 6.97 (d, J=5.3 Hz, 1H), 2.36 (t, J=7.7 Hz, 4H), 1.39-1.07 (m, 20H), 0.91-0.81 (m, 6H).
