piperidine; copper(l) iodide; tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran T=40°C; 3.5 h;

1.1: lithium hexamethyldisilazane / tetrahydrofuran; hexane / 1.75 h / -78 °C 1.2: 36 percent / tetrahydrofuran; hexane / 3.25 h / -78 - 20 °C 2.1: 7 percent / piperidine; CuI / Pd(P(C6H5)3)4 / tetrahydrofuran / 3.5 h / 40 °C View Scheme

1.1: lithium diisopropylamide / tetrahydrofuran / 1 h / -78 °C 1.2: 66 percent / dibromotetrachlorethane / tetrahydrofuran / 0.5 h / -90 °C 2.1: lithium hexamethyldisilazane / tetrahydrofuran; hexane / 1.75 h / -78 °C 2.2: 36 percent / tetrahydrofuran; hexane / 3.25 h / -78 - 20 °C 3.1: 7 percent / piperidine; CuI / Pd(P(C6H5)3)4 / tetrahydrofuran / 3.5 h / 40 °C View Scheme