Sonogashira cross-coupling reactions catalysed by heterogeneous copper-free Pd-zeolites

A heterogeneous [Pd(NH₃)₄]-NaY catalyst was applied to the copper-free Sonogashira cross-coupling of aryl halides with terminal alkynes. This copper-free heterogeneous Pd-catalyst is efficient, stable and recyclable. Aryl iodides and activated aryl bromides were converted quantitatively using 1 mol % Pd-catalyst to the corresponding diaryl-substituted alkynes within 3 h.