Synthesis of a combinatorial library of chiral ligands for asymmetric transition metal catalysis is proposed. The bidentate ligands will be assembled from unnatural amino acids and chiral amino alcohols. The modular framework provides a variety of binding geometries and chiral environments for the chelating bisphosphinites. The library will be screened for asymmetric induction in two well studied reactions: Pd- catalyzed allylic amidation and Rh-catalyzed enamide hydrogenation. Finally, the asymmetric ligand libraries will be applied to a previously achiral Rh-catalyzed diene cyclization reaction. The discovery of new chiral catalysts is important in expanding the synthetic procedures for production of enantiomerically pure drugs. If successful, the proposed strategy would provide an new and rapid method for the development and synthesis of asymmetric ligands for enantioselective catalytic processes.
