1: (3-dibromomethylene-penta-1,4-diynyl)-benzene With n-butyllithium in hexane; toluene T=-40 - -20°C; Fritsch-Buttenburg-Wiechell rearrangement; 2: With zinc(II) chloride in tetrahydrofuran; hexane; toluene T=-40 - 0°C; 3: iodobenzene With tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran; hexane; toluene T=70°C; Negishi coupling; 20 h;

1: (3-dibromomethylene-penta-1,4-diynyl)-benzene With n-butyllithium in hexane; toluene T=-40 - -20°C; Fritsch-Buttenburg-Wiechell rearrangement; 2: With zinc(II) chloride in tetrahydrofuran; hexane; toluene T=-40 - 0°C; 3: 1-(1-iodoethynyl)-4-methylbenzene With tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran; hexane; toluene T=70°C; Negishi coupling; 20 h;

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