Potassium hexacyanoferrate(II)--a new cyanating agent for the palladium-catalyzed cyanation of aryl halides.

A new advantageous cyanating agent, potassium hexacyanoferrate(II), is described for the palladium-catalyzed cyanation of aryl halides. All cyanide ions on the iron(II) center can be transferred to the aryl halide using palladium(II) acetate and dppf as the catalyst. Under optimized reaction conditions good yields of benzonitriles and unprecedented catalyst productivities are observed.