1.1: butyllithium; 2,2,6,6-tetramethylpiperidine / tetrahydrofuran / 0.25 h / -75 °C 1.2: methanol 2.1: 2 equiv. butyllithium / toluene; hexane / 1 h / -75 °C 2.2: 94 percent / toluene; hexane View Scheme

1: With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran T=-75°C; 0.25 h; 2: With methanol