1.1: ZnCl2; hydroquinone / tetrahydrofuran / 2 h / 0 °C 1.2: 70 percent / acetic acid; H2O 2.1: 70 percent / LiCl; DBU / tetrahydrofuran / 1 h / -78 °C 3.1: 85 percent / TMSOTf / CH2Cl2 / 20 h / -78 °C 4.1: 65 percent / MeONa / benzene / 12 h / Heating 5.1: 90 percent / MgCl2 hexahydrate / dimethylsulfoxide / 4 h / 130 °C View Scheme