1: piperidin-2-one With n-butyllithium in tetrahydrofuran; hexane T=0°C; 1 h; 2: ethyl iodide in tetrahydrofuran; hexane T=0°C; 0.75 h;

1.1: t-BuLi / hexane; tetrahydrofuran / 0.25 h / -78 - 0 °C 1.2: 68 percent / hexane; tetrahydrofuran / -78 - 20 °C 2.1: 81 percent / aq. HCl / CHCl3 3.1: 91 percent / aq. K2CO3 / methanol / 24 h View Scheme

1: 81 percent / aq. HCl / CHCl3 2: 91 percent / aq. K2CO3 / methanol / 24 h View Scheme

T=220°C;