A DFT study of pyramidalized alkenes : 7-oxasesquinorbornenes and 7,7'-dioxasesquinorbornenes

DFT calculations of 7¢–oxasesquinorbornenes and 7,7¢-dioxasesquinorbornenes using the B3LYP/6– 31G* method are reported. All the investigated structures (syn- and anti- derivatives) showed significant non-planarity of the central double bond, with the exception of those anti-derivatives possessing symmetrical structures. The influence of the replacement of the methylene groups at position 7- of the norbornene fragment with oxygen and the introduction of second and third (peripheral) double bonds and benzene rings on the molecular and electronic structures of these molecules have also been investigated.