1: carbon tetrabromide With triphenylphosphine in dichloromethane T=0°C; 0.05 h; 2: trans-4-phenyl-2-butenal in dichloromethane T=0°C; 3 h; Further stages.;

1.1: 94 percent / DIBAL-H / toluene; tetrahydrofuran / 2 h / -78 - -10 °C 2.1: 81 percent / PCC / CH2Cl2 / 2.5 h / 20 °C 3.1: PPh3 / CH2Cl2 / 0.05 h / 0 °C 3.2: 84 percent / CH2Cl2 / 3 h / 0 °C View Scheme

1.1: 81 percent / PCC / CH2Cl2 / 2.5 h / 20 °C 2.1: PPh3 / CH2Cl2 / 0.05 h / 0 °C 2.2: 84 percent / CH2Cl2 / 3 h / 0 °C View Scheme