1: 56 percent / potassium hydroxide, potassium ferricyanide / H2O / 6 h / Ambient temperature 2: 72 percent / AlI3, tetra-n-butylammonium iodide / benzene / 7 h / Heating View Scheme

With  potassium hydroxide; potassium hexacyanoferrate(III) in  water 6 h;  Ambient temperature;