n-butyllithium in tetrahydrofuran; hexane T=-75°C; 0.75 h;

1: 69 percent / polyphosphoric acid / 2 h / 150 °C 2: 84 percent / phosphorus oxybromide / 2 h / 150 °C 3: 83 percent / butyllithium / tetrahydrofuran; hexane / 0.75 h / -75 °C View Scheme

1: 84 percent / phosphorus oxybromide / 2 h / 150 °C 2: 83 percent / butyllithium / tetrahydrofuran; hexane / 0.75 h / -75 °C View Scheme