1.1: butyllithium / tetrahydrofuran; hexane / 1 h / -70 °C 1.2: tetrahydrofuran; hexane / -70 - 20 °C 2.1: butyllithium / tetrahydrofuran; hexane / 1 h / 0 °C 2.2: 1.16 g / tetrahydrofuran; hexane / 1 h / 20 °C View Scheme

n-butyllithium 1) THF, 0 deg C, 1.3 h, 2) 0 deg C, 30 min, then RT, 90 min; Yield given. Multistep reaction;

n-butyllithium 1) THF, 0 deg C, 1.5 h; Yield given. Multistep reaction;