1: 73 percent / Pd(PPh3)4; K2CO3 / tetrahydrofuran / 24 h / 65 °C 2: 93 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 2 h / 0 °C 3: 83 percent / TpRuPPh3(CH3CN)PF6 / 1,2-dichloro-ethane / 24 h / 80 °C View Scheme

Na2S*9H2O in 1-methyl-pyrrolidin-2-one T=185 - 195°C; 12 h; Inert atmosphere;

1: [(2,5-dibromobenzene-1,4-diyl)diethyne-2,1-diyl]-bis(trimethylsilane) With n-butyllithium in diethyl ether; hexane T=-78°C; 1 h; 2: tri-isopropylsylil trifluoromethane sulfonate in diethyl ether; hexane T=-78 - 20°C;

1.1: n-BuLi / diethyl ether; hexane / 1 h / -78 °C 1.2: 11 percent / diethyl ether; hexane / -78 - 20 °C 2.1: 85 percent / K2CO3; MeOH / tetrahydrofuran / 5 h / 20 °C View Scheme

1: [(2,5-dibromobenzene-1,4-diyl)diethyne-2,1-diyl]-bis(trimethylsilane) With n-butyllithium in diethyl ether; hexane T=-78°C; 1 h; 2: Et2NMe2SiCl in diethyl ether; hexane T=-78 - 20°C; 3: ethanol With ammonium chloride in diethyl ether; hexane T=20°C; 5 h;

1.1: n-BuLi / diethyl ether; hexane / 1 h / -78 °C 1.2: diethyl ether; hexane / -78 - 20 °C 1.3: 48 percent / NH4Cl / diethyl ether; hexane / 5 h / 20 °C 2.1: 75 percent / potassium carbonate / tetrahydrofuran; ethanol / 30 h / 20 °C View Scheme