|M.Sc Student||Borovoi Iris|
|Subject||Design and Synthesis of Novel Multifarenes|
|Department||Department of Chemistry||Supervisor||PROFESSOR EMERITUS Ehud Keinan|
Macrocycles offer a variety of useful applications in many areas. In recent years chiral macrocycles have attracted increasing attention due to their potential applications as enantioselective receptors and mediators in asymmetric catalysts. The new family of multifarenes macrocycles offers high modularity of its members and variety of possible substituents. This opens a wide range of possibilities for synthesis of chiral multifarenes.
We aimed at synthesizing several chiral multifarenes, using various synthetic strategies. The “n minus 1” multifarene synthesis worked well for the insertion of one chiral unit into the cyclic multifarene. The result of this synthesis was the first chiral multifarene possessing one chiral thiourea unit. The multistep synthesis of multifarenes was also used for the synthesis of chiral multifarene [3,3]. Although trans-cyclohexane diamine could not be used for this approach, probably due to steric problems, the synthesis was successfully achieved with cis-1,2-diphenyl-1,2-diaminoethane. Starting with non-chiral reactants, the synthesis of asymmetric multifarenes[2,2] might be possible using this strategy with bulkier functional groups.
A synthetic pathway was designed for the synthesis of multifarene having molecular asymmetry but no asymmetric centers. This approach has demonstrated that this type of chirality is possible for multifarenes and can be achieved relatively easily and therefore should be pursued in future studies.
The metal binding properties of multifarenes was studied qualitatively with multifarene[3,3] and ion complexes of mercury(II) and palladium (II). The results show that multifarene[3,3] can create complexes with mercury(II) and palladium (II) ions . These observations suggest that chiral multifarenes could play an important role as ligands in metal-catalyzed asymmetric synthesis. These opportunities are currently under investigations in our laboratories.