2: LiOH / methanol; tetrahydrofuran / 10 h / 55 °C 4: 70 percent / dimethylaluminium chloride, fumaronitrile / 1,2-dichloro-ethane / 48 h / 10 °C 5: 86 percent / HF/pyridine / tetrahydrofuran / 12 h / 45 °C View Scheme