1: 97 percent / tetrahydrofuran / Heating 2: 85 percent / H2SO4 / 1.5 h / Heating View Scheme

1: 99 percent / tetrahydrofuran / Heating 2: 77 percent / H2SO4 / 1.5 h / Heating View Scheme

1: 98 percent / tetrahydrofuran / Heating 2: 69 percent / H2SO4 / 1.5 h / Heating View Scheme

selenium; carbon monoxide; water in tetrahydrofuran; triethylamine T=100°C; P=22501.8 Torr; 3 h;

1: 99 percent / tetrahydrofuran / Heating 2: 77 percent / H2SO4 / 1.5 h / Heating 3: 83 percent / NaOAc, NH2OH*HCl / ethanol; H2O 4: 68 percent / Zn, NH4OAc, aq. NH3 / ethanol / Heating 5: 89 percent / Na2CO3 / CH2Cl2 / Ambient temperature View Scheme