1: 4-(but-2-ynyloxymethyl)-1-(methanesulphonyl)-piperidine With lithium hexamethyldisilazane in tetrahydrofuran T=-17°C; Wadsworth-Emmons Reaction; 0.5 h; 2: With diethyl chlorophosphate in tetrahydrofuran T=0°C; 0.833333 h; 3: acetaldehyde in tetrahydrofuran 15 h;