A Theoretical Study on Bromonium Ion and Mercurinium Ion Intermediates

Geometries of two title intermediates brought about by bromination and oxymercuration are studied with PM3 and ab initio molecular orbital calculations. For thirteen Br+ intermediates, the regular Markovnikov type structures are obtained and they depend upon the electronic donating strength. On the other hand, geometries of thirteen Hg(OCOCH3)2 intermediates are found to be almost the same and of the isosceles-triangle forms. Steric repulsion occurs not between two acetate groups but between one acetate and the substituents attached to olefins.