selenium(IV) oxide in ethanol T=70°C; 38 h;

1: 89 percent / benzyltriethylammonium chloride, sodium hydroxide / H2O / 4 h / 45 - 50 °C 2: 22 percent / aq. HCl / 2 h / Heating 3: 84 percent / selenium dioxide / ethanol / 38 h / 70 °C View Scheme

1: 22 percent / aq. HCl / 2 h / Heating 2: 84 percent / selenium dioxide / ethanol / 38 h / 70 °C View Scheme

1: 26 percent / n-butyllithium / tetrahydrofuran / -78 deg C, 0.5 h, then warm up to room temperature (1 h) 2: 84 percent / selenium dioxide / ethanol / 38 h / 70 °C View Scheme