sodium tetrahydroborate in trifluoroacetic acid T=0°C; 0.25 h;

1: 1) Mg, 1,2-Dibromoethane / 1) in THF under refluxtemp., 2) under cooling, 45 min -> 12 h, refluxtemp. 2: 94 percent / PBr3, Py. / benzene / 2 h 3: 89 percent / methanol / 2.5 h / Heating 4: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 5: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 93 percent / NaBH4 / tetrahydrofuran / 3.5 h / 20 °C 2: 94 percent / PBr3, Py. / benzene / 2 h 3: 89 percent / methanol / 2.5 h / Heating 4: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 5: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 88 percent / diisobutylaluminium hydride / hexane; benzene / 3 h / 20 °C 2: 93 percent / NaBH4 / tetrahydrofuran / 3.5 h / 20 °C 3: 94 percent / PBr3, Py. / benzene / 2 h 4: 89 percent / methanol / 2.5 h / Heating 5: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 6: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 94 percent / PBr3, Py. / benzene / 2 h 2: 89 percent / methanol / 2.5 h / Heating 3: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 4: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 89 percent / methanol / 2.5 h / Heating 2: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 3: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 2: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 2: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme

1: 84 percent / diisobutylaluminium hydride / benzene; hexane / 12 h 2: 1) Mg turnings, 1,2-dibromoethane / 1) in THF, 6-8 h, under reflux, 2) in THF, 1 h, 20 deg C -> 1h, reflux 3: 94 percent / NaBH4 / trifluoroacetic acid / 0.25 h / 0 °C View Scheme