1.1: LiTMP / tetrahydrofuran / 4 h / 0 °C 1.2: tetrahydrofuran / -110 - 20 °C 2.1: 7.5 g / aq. HCl / pentane / 1 h / 20 °C 3.1: diphenyltetramethyldisilazane; n-butyl lithium / tetrahydrofuran / 1 h / -78 °C 3.2: NEt3 / tetrahydrofuran / 5 h / 20 °C 4.1: 57 percent / BF3*OEt2 / CH2Cl2 / 3 h / -78 °C 5.1: 90 percent / SmI2 / tetrahydrofuran / 1 h / -15 °C 6.1: 53 percent / proton sponge / CH2Cl2 / 6 h / 40 °C 7.1: 60 percent / aq. HCl / acetone / 1.33 h / 20 °C 8.1: 48 percent / NEt3 / tetrahydrofuran; CH2Cl2 / 0.5 h / 0 °C 9.1: 32 percent / titanium tetraisopropoxide / Grubbs first-generation catalyst / CH2Cl2 / 20 h / Heating 10.1: 80 percent / aq. HCl / methanol / 60 °C View Scheme