Synthesis, Molecular Structure, and Chiroptical Properties of Dibenzylidene Derivatives of Bicyclo[3.3.1]nonane and Brexane.
Author
Summary, in English
Synthesis of several enantiomerically pure unsaturated bicyclo[3.3.1]nonane and related brexane (tricyclo[4.3.0.0(3,7) ]nonane) derivatives bearing exocyclic benzylidene substituents from readily available (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione was accomplished. Molecular geometry and chiroptical properties of compounds with enone and styrene chromophores were studied by X-ray diffraction analysis, molecular modeling, and circular dichroism (CD) spectroscopy. Difunctional 3,7-dibenzylidenebicyclo[3.3.1]nonanes, such as and , exhibited intense CD couplets, arising from the exciton coupling between the two unsaturated chromophores. The observed negative sign of the exciton couplets is congruent with the negative twist (negative chirality) defined by the two interacting transition dipoles. The sign of the Cotton effect corresponding to the π→π* transitions in the CD spectra of monoenone and tricyclic brexane acetate was correlated with the intrinsic dissymmetry (helicity) of the styrene chromophore. Chirality 27:728-737, 2015. © 2015 Wiley Periodicals, Inc.
Department/s
Publishing year
2015
Language
English
Pages
728-737
Publication/Series
Chirality
Volume
27
Issue
10
Document type
Journal article
Publisher
John Wiley & Sons Inc.
Topic
- Organic Chemistry
Status
Published
ISBN/ISSN/Other
- ISSN: 1520-636X