n-butyllithium in diethyl ether; hexane T=0°C; 1 h;

1: 94 percent / NaH / tetrahydrofuran; various solvent(s) / 12 h / 20 °C 2: 100 percent / n-BuLi / hexane; diethyl ether / 1 h / 0 °C View Scheme

Yield given. Multistep reaction;