1.1: NaH / tetrahydrofuran / 1 h / 20 °C 1.2: 53 percent / tetrahydrofuran / 12 h / 70 °C 2.1: (-)-sparteine; nBuLi / toluene; hexane / 1.5 h / -78 °C 3.1: TMEDA; tBuLi / tetrahydrofuran; pentane / 1 h / -78 °C 3.2: tetrahydrofuran; pentane / -78 °C 4.1: 93 mg / 1,2-dichloro-ethane / 3 h / Heating 5.1: 55 percent / MeSO3H; H2O / 16 h / Heating 6.1: Jones reagent / acetone / 0.08 h / 0 °C 7.1: 8.0 mg / aq. NaOH / methanol / 18 h / Heating View Scheme