Dr. David R. Tyler, Department of Chemistry, University of Oregon is supported by the Synthetic Organic Chemistry Program of the Chemistry Division for the development of metallacycles for the synthesis main group heterocycles by remote intramolecular C-H bond activation. A series of early transition metal vinyl complexes that present one or more sites for intramolecular C-H activation and that always include at least one site that is accessible for gamma-activation will be prepared. The chemo- and regio- selectivity of the C-H activation reactions by these complexes will be determined. Through systematic variation in the placement and nature of the substituents on the vinyl group and the nature of the transition metal, an understanding of the steric and electronic factors favoring remote activation will be developed. The resulting information will be used to assist in the rational preparation of metallacyclic complexes, particularly metallacyclobutenes bearing substituent patterns unavailable through the use of existing synthetic procedures. There metallacyclic complexes will be exploited, with primary focus on the development of catalytic uses of the complexes in the formation of heterocyclic compounds. Transition metals are often used to effect the preparation of important organic chemicals. This project aims at developing new methods to prepare a variety of heretofore difficult to obtain species. These `heterocyclic` compounds have great laboratory, industrial, and biological significance. In addition, this project will explore the activation of carbon-hydrogen bonds that are remote from a transition metal. This phase of the investigation will provide fundamental information on how organic compounds can be activated by transition metals.
