Synthesis of Aza-Stilbenes via an Ullmann C-N Coupling Reaction in Ionic Liquids

Significance

The first protocol for the synthesis of aza-stilbenes in an ionic liquid is reported. Although substituent effects have not been widely studied, the reaction proceeds in good to excellent yields at comparable temperatures to standard Ullmann procedure. Since copper-amino acid complexes are known, the function of l-proline is undoubtedly to act as a solubilizing/activating ligand.