1: (3-dibromomethylene-penta-1,4-diynyl)-benzene With n-butyllithium in hexane; toluene T=-20 - 0°C; Fritsch-Buttenburg-Wiechell rearrangement; 2: methyl iodide in diethyl ether; hexane; toluene T=-20 - 20°C;

1: (E)-1-chloro-6-phenyl-1-hexene-3,5-diyne With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 1 h; 2: methyl iodide in tetrahydrofuran; hexane T=-78 - 20°C;

diisopropylamine; tetrakis(triphenylphosphine) palladium(0) in N,N-dimethyl-formamide T=20°C; 70 h;

n-butyllithium in hexane T=-78 - -40°C; Fritsch-Buttenberg-Wiechell rearrangement; 0.5 h;

1: NBS; AgF / acetonitrile / 1 h / 20 °C 2: 60 percent / i-Pr2NH / Pd(PPh3)4 / dimethylformamide / 70 h / 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 - -30 °C 1.2: 78 percent / ZnBr2 / Pd(PPh3)4 / tetrahydrofuran; hexane / 6 h / 0 °C 2.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 94 percent / tetrahydrofuran; hexane / -78 - 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 92 percent / ZnBr2 / Pd(PPh3)4 / tetrahydrofuran; hexane / 0 - 23 °C 2.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 - -30 °C 2.2: 78 percent / ZnBr2 / Pd(PPh3)4 / tetrahydrofuran; hexane / 6 h / 0 °C 3.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 94 percent / tetrahydrofuran; hexane / -78 - 20 °C View Scheme

1.1: 77 percent / potassium carbonate / tetrahydrofuran; methanol / 20 °C 2.1: BuLi / toluene; hexane / -20 - 0 °C 2.2: 65 percent / diethyl ether; toluene; hexane / -20 - 20 °C View Scheme

1: 56 percent / AlCl3 / CH2Cl2 / 3 h / 0 °C 2: 67 percent / PPh3 / CH2Cl2 / 20 °C 3: 48 percent / n-BuLi / hexane / 0.5 h / -78 - -40 °C View Scheme

1: 67 percent / PPh3 / CH2Cl2 / 20 °C 2: 48 percent / n-BuLi / hexane / 0.5 h / -78 - -40 °C View Scheme