Synthesis, Molecular Structure, and Chiroptical Properties of Dibenzylidene Derivatives of Bicyclo[3.3.1]nonane and Brexane.

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Abstract

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.

Detaljer

Författare
  • Sigitas Stončius
  • Algirdas Neniškis
  • Nagarajan Loganathan
  • Ola Wendt
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Organisk kemi
Originalspråkengelska
Sidor (från-till)728-737
TidskriftChirality
Volym27
Utgivningsnummer10
StatusPublished - 2015
PublikationskategoriForskning
Peer review utfördJa