1.1: BuLi / tetrahydrofuran; hexane / 0.33 h / -78 °C 1.2: 53 percent / tetrahydrofuran / -78 - -30 °C 2.1: LHMDS / tetrahydrofuran / -78 °C 2.2: 70 percent / MoOPH / tetrahydrofuran / -78 °C 3.1: 100 percent / DBU / tetrahydrofuran / 20 °C View Scheme