1: p-toluenesulfonic acid hydrate / acetone / 12 h / Ambient temperature 2: 85 percent / Li, ethylenediamine / tetrahydrofuran / 2 h / 25 °C / continuous flow of ethyne View Scheme

1: 85 percent / NaH / dimethylsulfoxide; toluene / 12 h / 80 °C / sonification 2: p-toluenesulfonic acid hydrate / acetone / 12 h / Ambient temperature 3: 85 percent / Li, ethylenediamine / tetrahydrofuran / 2 h / 25 °C / continuous flow of ethyne View Scheme

1: boron trifluoride diethyl ether / methanol / 1 h / Ambient temperature 2: 87 percent / Li, ethylamine / tetrahydrofuran / 0.5 h / -35 - -30 °C 3: 85 percent / SO3 pyridine complex / triethylamine; dimethylsulfoxide / 3 h / Ambient temperature 4: 85 percent / triethylorthoformate, p-toluenesulfonic acid hydrate / 3 h / 40 °C 5: 85 percent / NaH / dimethylsulfoxide; toluene / 12 h / 80 °C / sonification 6: p-toluenesulfonic acid hydrate / acetone / 12 h / Ambient temperature 7: 85 percent / Li, ethylenediamine / tetrahydrofuran / 2 h / 25 °C / continuous flow of ethyne View Scheme

1: 94 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 2: 79 percent / HC(OEt)3, p-TsOH*H2O / CH2Cl2 / 7 h / Heating 3: 88 percent / benzene; diethyl ether / 3 h / 10 - 15 °C 4: 74 percent / p-TsOH*H2O / formic acid / 7 h / 50 - 60 °C 5: 98 percent / BF3*Et2O / methanol / 2.5 h / 0 - 5 °C 6: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 7: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 8: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 9: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 88 percent / benzene; diethyl ether / 3 h / 10 - 15 °C 2: 74 percent / p-TsOH*H2O / formic acid / 7 h / 50 - 60 °C 3: 98 percent / BF3*Et2O / methanol / 2.5 h / 0 - 5 °C 4: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 5: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 6: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 7: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 79 percent / HC(OEt)3, p-TsOH*H2O / CH2Cl2 / 7 h / Heating 2: 88 percent / benzene; diethyl ether / 3 h / 10 - 15 °C 3: 74 percent / p-TsOH*H2O / formic acid / 7 h / 50 - 60 °C 4: 98 percent / BF3*Et2O / methanol / 2.5 h / 0 - 5 °C 5: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 6: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 7: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 8: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 2: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 2: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 3: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 74 percent / p-TsOH*H2O / formic acid / 7 h / 50 - 60 °C 2: 98 percent / BF3*Et2O / methanol / 2.5 h / 0 - 5 °C 3: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 4: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 5: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 6: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

in tetrahydrofuran; ethylenediamine T=10 - 20°C; 4 h;