1: n-amyl iodide With n-butyllithium in diethyl ether; pentane T=-78 - 20°C; Inert atmosphere; 2: pyrylium tetrafluoroborate in tetrahydrofuran; diethyl ether; pentane T=-78°C; 4 h;

1: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 1 h, 2.) THF, hexane, a) -20 deg C, 3 h, b) from -78 deg C to RT, 1 h 2: 1.) CuI / 1.) ether, hexane, 2.) ether, hexane, -20 deg C, 3 h 3: 79 percent / DDQ, H2O / CH2Cl2 / 3 h / Ambient temperature 4: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 2 h, 2.) CH2Cl2, from -78 deg C to RT, 1 h View Scheme

in tetrahydrofuran T=-78°C; 4 h; Inert atmosphere;

lithium diisopropyl amide in tetrahydrofuran; hexane 1.) -78 deg C, 1 h, 2.) 25 deg C, 2 h; Yield given;