1.1: KH / tetrahydrofuran / 0.67 h 1.2: 88 percent / C2Cl6 / tetrahydrofuran / 2 h / 20 °C 2.1: KH / tetrahydrofuran / 0.5 h / 0 °C 2.2: t-BuLi / tetrahydrofuran / 20 h / -78 °C 2.3: 69 percent / aq. NaOH / tetrahydrofuran / 0.33 h / -78 - 0 °C View Scheme