1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 1 h; 2: With phosphorus trichoride in tetrahydrofuran; hexane T=-78 - 20°C; Further stages.;

1.1: LiOEt / ethanol / 6 h / 20 °C 2.1: I2 / toluene / 3 h / Heating 3.1: nBuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 77.4 percent / PCl3 / tetrahydrofuran; hexane / -78 - 20 °C View Scheme

1.1: LiOEt / ethanol / 6 h / 20 °C 2.1: I2 / toluene / 3 h / Heating 3.1: nBuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 77.4 percent / PCl3 / tetrahydrofuran; hexane / -78 - 20 °C View Scheme

1.1: I2 / toluene / 3 h / Heating 2.1: nBuLi / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 77.4 percent / PCl3 / tetrahydrofuran; hexane / -78 - 20 °C View Scheme