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. We have recently completed NMR studies of the p-allyl intermediate complexes. This provides a measure of the influence of the ligand substituent on the fragment that will ultimately form the new bond. 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.
p-Allyl Intermediates