in diethyl ether T=-78 - 20°C; 12.3333 h; Inert atmosphere;

in tetrahydrofuran; diethyl ether T=-10 - 20°C; Inert atmosphere;

1.1: (-)-sparteine; sec.-butyllithium / 3 h / -78 °C / |Inert atmosphere; |Schlenk technique 1.2: -78 °C / |Inert atmosphere; |Schlenk technique 2.1: tetrafluoroboric acid diethyl ether complex / dichloromethane / 0.5 h / 0 °C / |Inert atmosphere; |Schlenk technique 2.2: 1 h / |Inert atmosphere; |Schlenk technique View Scheme

2: NaNH2 / tetrahydrofuran / Heating View Scheme