Hammett Studies of P,N-Chiral Ligands

1. Hammett Studies of P,N-Chiral Ligands Richard C. Bunt Department of Chemistry and Biochemistry Middlebury College Middlebury, VT In this on-going research project we seek to further our fundamental understanding of how new chemical bonds form with a preference for only one of two possible three-dimensional orientations. This 3-D property of molecules, called chirality, is important for most biologically important molecules, many of which are used as drugs or other therapeutic agents. Understanding how these molecules can be formed under the influence of a palladium catalyst will improve our ability to make new and better chiral drugs. 4’-PHOX Ligands 5’-PHOX Ligands Based on the initial studies with 4-modified PHOX ligands, we have synthesized a number of the isomeric 5-substituted PHOX ligands and completed NMR studies of the p-allyl intermediate complexes. We are now studying these ligands in reactions to see how the substituents affect chirality transfer from ligand to product. Understanding this relationship is key to understanding how the 3-D chirality of the molecule is determined. This, in turn, will allow scientists to design better catalysts to make new molecules with specific types of 3-D chirality. Asymmetric Reactions