tetrabutylammomium bromide; potassium carbonate in N,N-dimethyl-formamide T=20°C;

1: 90 percent / potassium carbonate, tetrabutylammonium bromide / dimethylformamide / 20 °C 2: 69 percent / powdered NaOH / dimethylsulfoxide / 0.5 h / 20 - 25 °C View Scheme