1: With n-butyllithium T=-78 - 20°C; 2: With hydrogenchloride in methanol Heating; 3: With N,N,N',N',N'',N''-hexamethylphosphoric triamide; sodium hydride; dimethyl sulfoxide

1.1: n-BuLi / hexane; tetrahydrofuran / 0.75 h / -78 °C 1.2: 75 percent / hexane; tetrahydrofuran / 1.5 h / -78 - 20 °C 2.1: 67 percent / aq. HCl / methanol / 13 h / Heating 3.1: NaH / hexamethylphosphoric acid triamide 3.2: 59 percent / hexamethylphosphoric acid triamide / 2 h / 20 °C View Scheme