in diethyl ether T=-78°C;

1: 98 percent / HCl / ethanol / Heating 2: 85 percent / diethyl ether / Ambient temperature 3: DBU / tetrahydrofuran / 4 h / -5 °C 4: diethyl ether / -78 °C View Scheme

1: 93 percent / NaH / tetrahydrofuran / Heating 2: 75 percent / 2 M aq. H2SO4 / acetone / Heating 3: 98 percent / HCl / ethanol / Heating 4: 85 percent / diethyl ether / Ambient temperature 5: DBU / tetrahydrofuran / 4 h / -5 °C 6: diethyl ether / -78 °C View Scheme

1: 90 percent / TosOH / benzene / Heating 2: 93 percent / NaH / tetrahydrofuran / Heating 3: 75 percent / 2 M aq. H2SO4 / acetone / Heating 4: 98 percent / HCl / ethanol / Heating 5: 85 percent / diethyl ether / Ambient temperature 6: DBU / tetrahydrofuran / 4 h / -5 °C 7: diethyl ether / -78 °C View Scheme

1: 93 percent / NaH / tetrahydrofuran / Heating 2: 75 percent / 2 M aq. H2SO4 / acetone / Heating 3: 98 percent / HCl / ethanol / Heating 4: 85 percent / diethyl ether / Ambient temperature 5: DBU / tetrahydrofuran / 4 h / -5 °C 6: diethyl ether / -78 °C View Scheme

1: 75 percent / 2 M aq. H2SO4 / acetone / Heating 2: 98 percent / HCl / ethanol / Heating 3: 85 percent / diethyl ether / Ambient temperature 4: DBU / tetrahydrofuran / 4 h / -5 °C 5: diethyl ether / -78 °C View Scheme

1: 85 percent / diethyl ether / Ambient temperature 2: DBU / tetrahydrofuran / 4 h / -5 °C 3: diethyl ether / -78 °C View Scheme