1: BuLi / tetrahydrofuran 2: 64 percent / Et2O-BF3 / acetone; H2O View Scheme

1: BuLi / tetrahydrofuran 2: 64 percent / Et2O-BF3 / acetone; H2O 3: 93 percent / NaN3 / NaI / dimethylsulfoxide / 18 h / 55 °C 4: 76 percent / diethyl ether / 24 h / 20 °C View Scheme

1: 1.) n-BuLi / 1.) 0 deg C, 40 min, 2.) 15 h 2: 0.5 M aq. HCl / 1 h View Scheme

1: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 40 min, 2.) THF, hexane, RT 2: Amberlyst-15, H2O / acetone 3: 43 percent / p-benzoquinone, PdCl2, H2O / dimethylformamide / 3 h / 70 °C View Scheme