enantioselective ullmann reaction catalyzed by palladium carbene functionalized 2d coordination polymer

The ullmann coupling reaction is one of the most beneficial processes for the preparation of binary compounds [1, 2]. in this report, a heterogeneous chiral palladium catalyst has been applied in the ullmann coupling reaction. in this approach, a 2d coordination polymer of zinc-containing ditopic imidazolium-based dicarboxylate ligands attached to the palladium through a palladium-carbene bond (scheme 1). the structure of the catalyst was characterized by fourier transform infrared spectroscopy, x-ray powder diffraction, and 1h nmr spectroscopy after digestion in an alkaline solution. the structure of the chiral biphenyl was confirmed by 1h nmr spectroscopy.