1: 66 percent / Li, EtNH2 / Ambient temperature; further reagent 2: 78 percent / n-butyl-lithium, iodomethane / tetrahydrofuran / 2 h / 23 °C 3: 68 percent / Li, EtNH2 / Ambient temperature; further reagent 4: 53 percent / n-butyl-lithium / tetrahydrofuran; hexane / 1 h / -20 °C 5: 38 percent / K, 18-crown-6, t-BuNH2 / tetrahydrofuran / Ambient temperature View Scheme

1: 66 percent / Li, EtNH2 / Ambient temperature; further reagent 2: 78 percent / n-butyl-lithium, iodomethane / tetrahydrofuran / 2 h / 23 °C 3: 68 percent / Li, EtNH2 / Ambient temperature; further reagent 4: 53 percent / n-butyl-lithium / tetrahydrofuran; hexane / 1 h / -20 °C 5: 19 percent / K, 18-crown-6, t-BuNH2 / tetrahydrofuran / Ambient temperature View Scheme