n-butyllithium 1.) THF, hexane, -60 deg C, 15 min, 2.) THF, hexane, from -60 deg C to RT; Yield given. Multistep reaction;

1: 51 percent / Amberlyst 15 / 5 h / 21 °C 2: 1.) n-butyllithium / 1.) THF, hexane, -60 deg C, 15 min, 2.) THF, hexane, from -60 deg C to RT View Scheme