1.1: Et3N / CH2Cl2 / 0.25 h / -7 °C 2.1: 0.29 g / tetrahydrofuran; diethyl ether; hexamethylphosphoric acid triamide / 2 h / -78 - 20 °C 3.1: BF3*Et2O / CH2Cl2 / 2 h / -78 °C 4.1: Bu4NF / tetrahydrofuran / 23 °C 5.1: n-BuLi / tetrahydrofuran / -78 °C 5.2: Li; EtNH2 / tetrahydrofuran View Scheme