1: NaBH4 / methanol / 0.25 h / 0 °C 2: imidazole / dimethylformamide / 2.5 h / 50 °C 3: diisobutylaluminium hydride / CH2Cl2 / 0.08 h / -78 °C 4: pyridinium chlorochromate / CH2Cl2 / 2.5 h / Ambient temperature 5: 83 percent / 48percent aq. HF / acetonitrile / 2 h / Ambient temperature View Scheme

1: NaBH4 / methanol / 0.25 h / 0 °C 2: imidazole / dimethylformamide / 2.5 h / 50 °C 3: diisobutylaluminium hydride / CH2Cl2 / 0.08 h / -78 °C 4: pyridinium chlorochromate / CH2Cl2 / 2.5 h / Ambient temperature 5: 83 percent / 48percent aq. HF / acetonitrile / 2 h / Ambient temperature 6: 85 percent / pyridine / 4 h / Ambient temperature 7: t-BuOK / tetrahydrofuran 8: 100 percent / LiOH / propan-2-ol; H2O View Scheme

sodium tetrahydroborate in methanol T=0°C; 0.25 h;