1: pyridine, 4-dimethylaminopyridine / diethyl ether / 0.83 h 2: 65 percent / AgBF4 / benzene / 2.5 h / 80 °C 3: 92 percent / pyridinium p-toluenesulfonate / ethanol / 4 h / 50 °C 4: 92 percent / trioctylphosphine, carbon tetrabromide / diethyl ether / 0.22 h / 0 °C 5: 1.) butyllithium, 2.) 3-methoxy-3-methylbut-1-ynylcopper 6: 1.) LiAlH4, 2.) PCC, AcONa / 1.) Et2O, 10 min, 2.) dichloromethane, RT, 1 h 7: 62 percent / P2I4 / 0.42 h / 0 °C View Scheme