With support from the Organic Dynamics Program, Dr. Beak will utilize the "endocyclic restriction test" to investigate allowed geometries for reactions that occur at atoms which lack stereochemical features. In this approach, transfer of non-stereogenic heteroatoms is performed in systems wherein the bond forming group and the leaving group are joined by a chain. The size of the endocyclic ring required for intramolecular transfer limits the available reaction geometry. When taken in combination with other mechanistic tools, application of this approach should provide important, detailed information regarding the geometry of the transition states in atom-transfer reactions. The geometries of reactions at oxygen, nitrogen, halogen, sulfur, and hydrogen will be investigated. Mechanisms involving concerted, associative and/or dissociative steps are to be evaluated for each case. Other mechanistic probes, e.g., crossover experiments, kinetic studies, and determinations of intra- and intermolecular isotope effects, will be used to supplement results obtained via application of the endocyclic restriction test.
