1.1: BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 1.2: 90 percent / tetrahydrofuran; hexane / 2 h / -78 °C 2.1: LiCl; DBU / acetonitrile / 20 h 3.1: Zn(BH4)2 / diethyl ether / 2.5 h / -35 °C 4.1: BuLi / tetrahydrofuran / 0.25 h / 0 °C 4.2: tetrahydrofuran / 1 h / -78 °C 5.1: 91 percent / xylene / 4 h / Heating 6.1: Ba(OH)2 / methanol / 20 °C 7.1: KHCO3 / ethyl acetate; H2O / 20 °C 8.1: O3 / methanol / 0.33 h / -78 °C 8.2: Me2S / methanol / 1 h / -78 - 20 °C 8.3: 73 percent / Br2; NaHCO3; H2O / 20 °C View Scheme