Pyramidalized olefins : a DFT study of the homosesquinorbornene and sesquibicyclo[2.2.2]octene nuclei

Density functional theory (B3LYPl6-31G*) was used to study a series of homosesquinorbornenes and sesquibicyclo[2.2.2loctenes. The compounds in which the two faces of the double bond are different are predicted to have a pyramidal double bond with butterfly bendings (v) ranging from 1.8 to 17.9". The degree of pyramidalization of these central double bonds is greater in the homosesquinorbornenes than in the sesquibicyclo[2.2.2loctenes.