1.1: LDA / tetrahydrofuran / -78 - 20 °C 1.2: bis(cyclopentadienyl)zirconium dichloride / tetrahydrofuran / 1 h / -78 °C 1.3: 94 percent / tetrahydrofuran / 2.33 h / -105 °C 2.1: aq. H2SO4 / dioxane / 2 h / Heating View Scheme

lithium chloride; lithium diisopropyl amide in tetrahydrofuran T=0°C;