1: 61 percent / BF3*Et2O / CH2Cl2 / 3 h / -10 °C 2: 59 percent / N-methylpiperidone, aluminium isopropoxide / toluene / 3 h / Heating View Scheme

1: 1.) butyllithium / 1.) THF, hexane, 1.5 h, 20 deg C: 2.) THF, 66 deg C, 12 h 2: 262 mg / tetrabutylammonium fluoride / tetrahydrofuran / 20 °C 3: 1.) N-methyl piperidone; 2.) aluminium isopropoxide / 1.) toluene, boiling; 2.) toluene, 110 deg C, 5 h 4: 59 percent / IRN-77 Amberlite / acetone / 24 h / Ambient temperature View Scheme

n-butyllithium 1.) THF, hexane, 1.5 h, 20 deg C: 2.) THF, 66 deg C, 12 h; Yield given. Multistep reaction;

n-butyllithium 1.) THF, hexane, 3 h, r.t.; 2.) THF, r.t., overnight; Yield given. Multistep reaction;

Multi-step reaction with 3 steps 1: 1.) butyllithium / 1.) THF, hexane, 1.5 h, 20 deg C: 2.) THF, 66 deg C, 12 h2: 262 mg / tetrabutylammonium fluoride / tetrahydrofuran / 20 °C3: 1.) N-methyl piperidone; 2.) aluminium isopropoxide / 1.) toluene, boiling; 2.) toluene, 110 deg C, 5 h