2,2,6,6-tetramethylpiperidinyl-lithium in tetrahydrofuran; pentane T=25°C; 4 h; Inert atmosphere;

piperidine; C20H26Br2N2O4Pd2 in 1-methyl-pyrrolidin-2-one T=100°C; Sonogashira Cross-Coupling; 0.5 h;

triethylamine; palladium diacetate; triphenylphosphine T=80 - 85°C; 18 h;

1: 1.) n-BuLi, 2.) I2 / 1.) ether, hexane, 30 min, 0 deg C; 2 h, 25 deg C, 2.) 2 h, 25 deg C 2: 44 percent / triethylamine / palladium(II) acetate, triphenylphosphine / 18 h / 80 - 85 °C View Scheme