1: 83 percent / DBU / tetrahydrofuran / 4 h / Ambient temperature 2: 1.) NaH / 1.) THF, 0 deg C, 30 min, 2.) 0 deg C, 3 h 3: 78 percent / n-BuLi / tetrahydrofuran; hexane / 7 h / -78 - 20 °C 4: 81 percent / NaI, trimethylsilyl chloride / acetonitrile / 3 h / Ambient temperature View Scheme

Multi-step reaction with 2 steps 1: 83 percent / DBU / tetrahydrofuran / 4 h / Ambient temperature2: 1.) NaH / 1.) THF, 0 deg C, 30 min, 2.) 0 deg C, 3 h  

Multi-step reaction with 3 steps 1: 83 percent / DBU / tetrahydrofuran / 4 h / Ambient temperature2: 1.) NaH / 1.) THF, 0 deg C, 30 min, 2.) 0 deg C, 3 h3: 78 percent / n-BuLi / tetrahydrofuran; hexane / 7 h / -78 - 20 °C