1.1: 63 percent / LDA / -78 - 20 °C 2.1: 76 percent / LiAlH4 / tetrahydrofuran / 20 °C 3.1: 70 percent / DDQ / benzene / 20 °C 4.1: DBU; H(CF2)2O(CF2)2SO2F / tetrahydrofuran / 0.5 h / 0 °C 4.2: 82 percent / Et3N / tetrahydrofuran / 8 h / Heating 5.1: O3 / methanol / -78 °C 5.2: 67 percent / Me2S / 20 °C 6.1: 69 percent / aq. HCl / tetrahydrofuran / 1 h / 20 °C View Scheme