2: 67 percent / 1N HCl / 10 h / Ambient temperature 3: 1.) NaH / 1.) ether, 0.5h, room temp.; 2.) ether, 8h, reflux 4: 1.) copper(I) iodide / 1.) ether, -30 degC, 30 min; 2.) -78 degC, 1h View Scheme

2: 67 percent / 1N HCl / 10 h / Ambient temperature 3: 1.) NaH / 1.) ether, 0.5h, room temp.; 2.) ether, 8h, reflux 4: 1.) copper(I) iodide / 1.) ether, -30 degC, 30 min; 2.) -78 degC, 1h View Scheme

copper(l) iodide 1.) ether, -30 degC, 30 min; 2.) -78 degC, 1h; Yield given. Multistep reaction;