Optically Activity in Remotely Perturbated Exocyclic s-cis-Butadienes. Preparation and Circular Dichroism of Enatiomerically Pure 5,6-dimethylidene-2-norbornyl Derivatives

Article abstract of DOI:10.1002/hlca.19800630431

Optically pure 5,6-dimethylidene-exo-2-norbornanol ((+)-1, acetate ((+)-2), p-bromobenzenesulfonate ((+)-3), 5,6-dimethylidene-endo-2-norbornanol ((+)-3), 5,6-dimethylidene-endo-2-norbornanol ((+)4), acetate((+)-5, p-bromobenzenesulfonate((+)-6) and 5,6-dimethylidene-2-norbornanone((+)-7) have been prepared.Their chirality was correlated chemically with that proposed by Mislow et al. for (+)-benzo-5-norbornen-2-yl acetate ((+)-14).The solution CD. spectra of these remotely perturbed exocyclic s-cis-butadienes are reported and discussed briefly.Unexpectedly, the β,γ-unsaturated ketone (+)-7, for which transannular interaction between the ketone and diene funtions was revealed by its UV. absortion spectrum, showed (in isooctane) two weak Cotton effects of opposite sign between 265 and 340 nm.