1: CuBr; [Pd(PPh3)4] / dioxane / 15 h / Heating 2: aq. HCl / diethyl ether / 15 h / 20 °C View Scheme

sodium hydride in dimethyl sulfoxide T=0 - 20°C; 15 h;

1: 1) NaH / 1) ether-DMF, 15 min.; 2) 20 min. 2: 1) t-BuLi; 2) ethylene iodochloride in THF / 1) ether, -78 deg C 0.5 h View Scheme

1-chloro-2-iodo-ethane; tert.-butyl lithium 1) ether, -78 deg C 0.5 h; Yield given. Multistep reaction. Yields of byproduct given;

1.1: 2,2,6,6-tetramethylpiperidine; BuLi / tetrahydrofuran; hexane / 1 h / -50 °C 1.2: B(OMe)3 / tetrahydrofuran; hexane / 2 h / -75 °C 1.3: 78 percent / aq. AcOH; AcOOH / tetrahydrofuran; hexane / -75 - 20 °C 2.1: 71 percent / Ag2CO3 / tetrahydrofuran / 15 h / 20 °C 3.1: [Pd(PPh3)4]; CuBr / dioxane / 15 h / Heating 4.1: aq. HCl / diethyl ether / 15 h / 20 °C 5.1: 70 percent / aq. HBr / acetic acid / 5 h / Heating View Scheme