1.1: 96.8 percent / MsCl; 2,6-dimethylpyridine; LiCl / dimethylformamide / 4 h / -5 °C 2.1: BuLi / hexane; tetrahydrofuran; hexamethylphosphoric acid triamide / 0.5 h / -70 °C 2.2: 75.8 percent / hexane; tetrahydrofuran; hexamethylphosphoric acid triamide / 3 h / -70 - 20 °C 3.1: EtNH2; Li / tetrahydrofuran / 0.5 h / -78 °C 3.2: 86.1 percent / isoprene; NH4Cl / tetrahydrofuran 4.1: 93 percent / aq. HCl / methanol; hexane / 4 h / 40 °C View Scheme