1: With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-75°C; 2 h; 2: With n-butyllithium in diethyl ether; hexane T=-100°C; 0.25 h;

1: diisopropylamine; butyllithium / hexane; tetrahydrofuran / 2 h / -75 °C 2: 89 percent / butyllithium / diethyl ether; hexane / 0.25 h / -100 °C 3: 93 percent / butyllithium / diethyl ether; hexane / 0.25 h / -75 °C View Scheme

n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-75°C; 2 h;