ICMUB - News

Vendredi 29 juin 2007 : Conf du Dr Irena G. Stara, Institut de Chimie Organique et de Biochimie, Prague

Recent advances in the synthesis of nonracemic helical aromatics

Asymmetric synthesis of helicenes and their congeners is supposed to be the most straightforward and efficient route to single enantiomers of these attractive, helically chiral aromatic compounds. In spite of the latest achievements, practical asymmetric synthesis of helical aromatics has so far remained a challenging task.
Recently, we have contributed to solving this problem by synthesizing nonracemic [7]helicene-like scaffolds using diastereoselective [2+2+2] cycloisomerisation of centrally chiral aromatic triynes. Herein, we report the utilisation of this methodology in the synthesis of functionalised penta-, hexa- and heptacyclic aromatics in a nonracemic form. We also provide a detailed view of the origin of diastereoselectivity of the cyclisation.
Although these robust and relatively rigid helicene-like compounds are not fully aromatic systems like parent helicenes, they mimic well their molecular shape. A helically chiral platform has been rather unexplored in asymmetric catalysis. The preliminary results have shown the helicene-based ligands can serve as efficient chiral inducers in iridium catalysed allylic amination.
The other approaches to nonracemic helicene or helicene-like derivatives will be discussed as well as their physico-chemical properties and use.

Télécharger l'affiche (pdf, 60 Ko).
Contact : Sylvain Jugé

ICMUB (UMR 5260) - University of Burgundy - Dijon (France)