n-butyllithium; potassium tert-butylate 1) hexane, r.t., 15 h, 2) r.t., overnight; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;

n-butyllithium; N,N,N',N,-tetramethylethylenediamine 1) hexane, 12 h, r.t., 2) 24 h; Yield given. Multistep reaction;

isopentyl nitrite in 1,4-dioxane; 1,2-dichloro-ethane 0.75 h; Heating;

Multi-step reaction with 5 steps 1: dimethylformamide / 5 h / 160 °C2: dimethylformamide3: 67 percent / dimethylformamide / 22 h / 160 °C4: Na / N,N-dimethyl-acetamide / 15 h / 100 °C5: N,N-dimethyl-acetamide  

With  hydrogen bromide; acetic acid T=120 - 130°C;  Einleiten von CO2;