Lawesson's reagent in toluene Heating;

1.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 45 percent / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 40 percent / Lawesson's reagent / toluene / Heating View Scheme