1: 85 percent / tetrabutylammonium iodide, potassium hydroxide / tetrahydrofuran / 2 h / Ambient temperature 2: 41 percent / sodium iodide / dimethylformamide / 72 h / 50 °C 3: Na2Fe(CO)4 / tetrahydrofuran / 3 h / 25 °C / variation of nucleophile, solvent and time View Scheme

1: 85 percent / tetrabutylammonium iodide, potassium hydroxide / tetrahydrofuran / 2 h / Ambient temperature 2: 41 percent / sodium iodide / dimethylformamide / 72 h / 50 °C 3: 50 percent / Na2Fe(CO)4 / tetrahydrofuran / 3 h / 25 °C / variation of nucleophile, solvent and time View Scheme