ORGANIC SYNTHESIS REAGENTS BASED ON TRANSITION METALS

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The basic objective of the proposed research is the development of new reagents and synthetic strategies that allow the synthesis of complex organic molecules and polymers that are of biological interest. A family of complexes that contain metal-carbon double bonds and are active catalysts for the metathesis of olefins is now available. These complexes show a range of activities and functional group tolerance. These complexes have been demonstrated to be useful in the synthesis of a variety of cyclic olefins that are key intermediates in the synthesis of bioactive molecules. The design principles and techniques that are now available will be directed toward the use of these catalysts for the selective stereoselective synthesis of acyclic olefins and for the development of chiral complexes to be used in the kinetic resolution of chiral olefins and for the asymmetric cyclization of triolefins. Strategies are also being developed that will allow the modular synthesis of polyethers and the selective synthesis of polypeptides (both on and off of solid supports) with constrained geometries. To reach many of the synthetic goals, new catalysts will be prepared that contain steric asymmetries to induce desired double bond geometries, water soluble ligands for the conversion of water soluble substrates, and chiral ligands for asymmetric induction during C-C bond formation. All of these studies exploit the ability to form and cleave carbon-carbon double bonds at room temperature under neutral conditions in the presence of a wide variety of functional groups.