Exploration of heteroatom effects on reactive and structural properties of bicyclic systems

John Charlton

Document Type Dissertation/Thesis


Determinations of structural influences of heteroatoms has been attempted by chemical, analytical and theoretical methods. The structure of ammonium salts, epoxides and oxidation products have been used to determine ground state structures of flexible systems.4,S The theory behind these chemical methods lies in the fact that the products of these reactions should give two isomers, thus giving an indication of the presence or lack of a more hindered face and a clue to the overall structure of the starting material. The formation of an ammonium salt is predicted to have a low activation barrier and thus the formation of products should result in structures quite similiar to the reactants original structure.5 This method was particularly useful when determination of liquid phase structures was not possible. Since the salts formed are solids, X-ray patterns could be obtained and structures calculated. Analytical methods of stucture determination have been advanced greatly by the advent of high field NMR. Theoretical methods have also become more feasible in recent years thanks to progress in computational ease and availability of software. These methods when used in combination with each other, can provide great insight into the structures of both reactants and products of organic systems. Our group has long been concerned with understanding heteroatom effects on both a physical and theoretical level. Early work done includes hydrogenation and oxidation reactions, lanthanide shift studies and CNDO/2 calculations)