Copper(II) trans-bis-(glycinato): an efficient heterogeneous catalyst for cross coupling of phenols with aryl halides

Copper(II) trans-bis-(glycinato) complex, easily prepared by the solid state reaction of copper(II) acetate and glycine (trans-[Cu(glyo)2·H2O]) was found to be an efficient, recyclable, and high yielding catalyst for the Ullmann type synthesis of diaryl ethers via the cross coupling of phenols with aryl halides without using any additives at relatively low reaction temperature. The catalyst could easily be recovered by simple filtration and was reused for several runs with consistent catalytic activity.