Ammonia-driven chirality inversion and enhancement in enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate mediated by diguanidino-γ-cyclodextrin

J Am Chem Soc. 2014 May 14;136(19):6916-9. doi: 10.1021/ja5032908. Epub 2014 May 6.

Abstract

In the supramolecular photocyclodimerization of 2-anthracenecarboxylate mediated by 6(A),6(D)-diguanidino-γ-cyclodextrin (CD), the chiral sense and enantiomeric excess of the photoproduct were dynamic functions of temperature and cosolvent to afford the (M)-anti head-to-head cyclodimer in 64% ee in aqueous methanol at -70 °C but the antipodal (P)-isomer in 86% ee in aqueous ammonia at -85 °C, while the corresponding diamino-γ-CD host did not show such unusual photochirogenic behaviors. The ee landscape was very steep against the temperature and sign-inverted against the ammonia content to reveal the opposite temperature dependence at low and high ammonia contents, for which an altered solvent structure and/or guanidinium-carboxylate interaction mode would be responsible.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonia / chemistry*
  • Anthracenes / chemistry*
  • Carboxylic Acids / chemistry*
  • Cyclization
  • Dimerization
  • Guanidine / analogs & derivatives*
  • Light
  • Models, Molecular
  • Photochemical Processes
  • Stereoisomerism
  • gamma-Cyclodextrins / chemistry*

Substances

  • 2-anthracenecarboxylate
  • Anthracenes
  • Carboxylic Acids
  • gamma-Cyclodextrins
  • Ammonia
  • Guanidine
  • gamma-cyclodextrin