Optical activity in remotely perturbed exocyclic s-cis-butadienes. Preparation and circular dichroism of enantiomerically pure 5,6-dimethylidene-2-norbornyl derivatives
✍ Scribed by Jean-Marie Sonney; Pierre Vogel
- Book ID
- 102858484
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- German
- Weight
- 578 KB
- Volume
- 63
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Optically pure 5, 6‐dimethylidene‐exo‐2‐norbornanol ((+)‐1), acetate ((+)‐2), p‐bromobenzenesulfonate ((+)‐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 functions was revealed by its UV. absorption spectrum, showed (in isooctane) two weak Cotton effects of opposite sign between 265 and 340 nm.