Synthesis and structure of chiral 2,6-bis[(2-carbamoylphenyl)carbamoyl]pyridine ligands

Abstract The synthesis and structure of a series of enantiomerically pure 2,6-bis[(2-carbamoylphenyl)carbamoyl]-pyridine ligands (H 2 2a-c ) are described. Appended from the aryl groups are optically active groups which provide a chiral environment around the planar pyridine core. NMR and X-ray diffraction studies show that these ligands contain helical character which is maintained by a network of intramolecular hydrogen bonds. These ligands can bind metal ions through their tridentate diamidato-pyridyl chelate to form optically active metal complexes. The modular design of these ligands offers a variety of chiral environments about the metal chelate that can be useful in the synthesis of metal reagents for asymmetric transformations.