sulfuric acid in 1,4-dioxane T=140°C; 1 h;

chromium(VI) oxide; sulfuric acid in acetone 0.5 h; Ambient temperature;

chromium(VI) oxide; sulfuric acid; diisobutylaluminium hydride 1.) hexane, 2.) acetone; Yield given. Multistep reaction;

1: 58 percent / dimethylformamide / 16 h / 60 °C 2: 65 percent / DIBALH / CH2Cl2 / 3 h / -78 °C 3: 173 mg / CrO3; H2SO4 / acetone View Scheme

1: 81 percent / NaH, EtOH / diethyl ether / Heating 2: 94 percent / K2CO3, H2O / methanol / 48 h / Ambient temperature 3: Et3N / tetrahydrofuran / 1 h / Ambient temperature 4: tetrahydrofuran / 3 h / Ambient temperature 5: 95 percent / 4 N H2SO4 / tetrahydrofuran / 4 h / Heating 6: 81 percent / LiAlH4 / diethyl ether 7: 1.) Et3N / 1.) CH2Cl2, 10 min, 2.) CH2Cl2, RT, 1 h 8: 62 percent / 15-crown-5 / dimethylsulfoxide / Ambient temperature 9: 83 percent / i-Bu2AlH / benzene; hexane / 3 h / 0 °C 10: 76 percent / CrO3, aq. H2SO4 / acetone / 0.5 h / Ambient temperature View Scheme

1: 94 percent / K2CO3, H2O / methanol / 48 h / Ambient temperature 2: Et3N / tetrahydrofuran / 1 h / Ambient temperature 3: tetrahydrofuran / 3 h / Ambient temperature 4: 95 percent / 4 N H2SO4 / tetrahydrofuran / 4 h / Heating 5: 81 percent / LiAlH4 / diethyl ether 6: 1.) Et3N / 1.) CH2Cl2, 10 min, 2.) CH2Cl2, RT, 1 h 7: 62 percent / 15-crown-5 / dimethylsulfoxide / Ambient temperature 8: 83 percent / i-Bu2AlH / benzene; hexane / 3 h / 0 °C 9: 76 percent / CrO3, aq. H2SO4 / acetone / 0.5 h / Ambient temperature View Scheme

1: Et3N / tetrahydrofuran / 1 h / Ambient temperature 2: tetrahydrofuran / 3 h / Ambient temperature 3: 95 percent / 4 N H2SO4 / tetrahydrofuran / 4 h / Heating 4: 81 percent / LiAlH4 / diethyl ether 5: 1.) Et3N / 1.) CH2Cl2, 10 min, 2.) CH2Cl2, RT, 1 h 6: 62 percent / 15-crown-5 / dimethylsulfoxide / Ambient temperature 7: 83 percent / i-Bu2AlH / benzene; hexane / 3 h / 0 °C 8: 76 percent / CrO3, aq. H2SO4 / acetone / 0.5 h / Ambient temperature View Scheme