1.1: diisopropylamine / hexane; tetrahydrofuran / 2 h / -75 °C 1.2: butyllithium / tetrahydrofuran; diethyl ether; hexane / 0.25 h / -100 °C 1.3: 49 percent / butyllithium / hexane; diethyl ether / 0.25 h / -100 °C 2.1: butyllithium / hexane; tetrahydrofuran / 0.25 h / -75 °C 2.2: hexane; tetrahydrofuran View Scheme

1: With diisopropylamine in tetrahydrofuran; hexane T=-75°C; 2 h; 2: With n-butyllithium in tetrahydrofuran; diethyl ether; hexane T=-100°C; 0.25 h; 3: With n-butyllithium in diethyl ether; hexane T=-100°C; 0.25 h;

1: With diisopropylamine in tetrahydrofuran; hexane T=-75°C; 2 h; 2: With n-butyllithium in tetrahydrofuran; diethyl ether; hexane T=-100°C; 0.25 h; Title compound not separated from byproducts;

1: With diisopropylamine in tetrahydrofuran; hexane T=-75°C; 2 h; 2: With n-butyllithium in tetrahydrofuran; diethyl ether; hexane T=-100°C; 0.25 h; Title compound not separated from byproducts;