1: n-propyl-magnesium bromide With copper(l) iodide in tetrahydrofuran T=-78°C; 1 h; 2: toluene-4-sulfonic acid cyclopent-3-enyl ester in tetrahydrofuran T=-78 - -20°C;

dilithium tetrachlorocuprate in tetrahydrofuran; diethyl ether T=0°C; 0.5 h;

1: cyclopent-3-enyl bromide With magnesium in diethyl ether 2: 1-iodo-propane With dilithium tetrachlorocuprate in tetrahydrofuran; diethyl ether T=0 - 20°C; 12 h; Further stages.;

1.1: 90 percent / triphenylphosphane; bromine; pyridine / CH2Cl2 / 13 h / -15 - 20 °C 2.1: magnesium / diethyl ether 2.2: 30 percent / Li2CuCl4 / tetrahydrofuran; diethyl ether / 12 h / 0 - 20 °C View Scheme

1: 91 percent / LiAlH4 / diethyl ether / 3 h / 34 °C 2: 84 percent / Ph3P; iodine; imidazole / acetonitrile; diethyl ether / 2 h / 0 - 20 °C 3: 54 percent / Li2CuCl4 / diethyl ether; tetrahydrofuran / 0.5 h / 0 °C View Scheme

1: 84 percent / Ph3P; iodine; imidazole / acetonitrile; diethyl ether / 2 h / 0 - 20 °C 2: 54 percent / Li2CuCl4 / diethyl ether; tetrahydrofuran / 0.5 h / 0 °C View Scheme