1: 3,4-dibutyl-2-(trimethylsilylethynyl)thiophene With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78 - -30°C; 1 h; 2: N,N-dimethyl-formamide in tetrahydrofuran; hexane T=-78°C; 1 h;

1: 95 percent / aq. KOH / methanol; tetrahydrofuran 2: 97 percent / CuI; Pd(PPh3)4; triethylamine / 20 °C 3: 77 percent / I2; HgO / benzene / 3 h / 20 °C View Scheme

1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With iodine in tetrahydrofuran; hexane T=-78 - 20°C;

1.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 88 percent / I2 / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 78 percent / Pd(PPh3)4; CuI; triethylamine / 20 h / 50 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 88 percent / I2 / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 78 percent / Pd(PPh3)4; CuI; triethylamine / 20 h / 50 °C 3.1: 99 percent / aq. KOH / methanol; tetrahydrofuran / 1 h / 20 °C View Scheme

potassium hydroxide in tetrahydrofuran; methanol

1.1: 94 percent / K2CO3 / methanol / 1.5 h / 20 °C 2.1: 80 percent / CuI; iPr2NH / Pd(PPh3)2Cl2 / tetrahydrofuran / 20 °C 3.1: iPr2NH; n-BuLi / tetrahydrofuran; hexane / -78 - -30 °C 3.2: 89 percent / I2 / tetrahydrofuran; hexane / 1 h / -78 °C View Scheme