Cage Compounds: Building Blocks for Molecular Architecture
Cage compounds are characterized by three-dimensional structures which have defined rigid geometry and as such, they are very useful synthons in organic synthesis, as well as the indispensable substrates for the mechanistic studies. Moreover, the various atomic positions in a cage can serve as branching points where the additional ligating group can be introduced. These substituted derivatives can be used as building blocks in supramolecular chemistry. The first step towards employing cage compounds in the synthesis of more complex molecular systems is the understanding of their reactions.
This research project comprises the synthesis, and characterization of the cage compounds related to the derivatives of adamantane and pentacycloundecane (PCU).
In the first part of the proposed research project, the emphasis will be given to the investigation of the reaction mechanisms of the cage compounds, with special interest in ring-expansion reactions and photolytic decompositions of the corresponding diazo-compounds. In particular, we want to address the question of the intermediacy of carbene species in those reactions. In addition, some heteropolycyclic derivatives will be synthesized which should serve as substrates for studying photoinduced electron and hydrogen transfer.
Further work will be directed towards employing cage compounds in the synthesis of new ion receptors, cyclic peptides and depsipeptides. In the scope of this research we plan to synthesize new macrocyclic polythioethers and lactones, which contain aliphatic cage molecule incorporated into the macrocyclic ring. These molecules should exhibit cation binding properties. We plan to extend these studies towards the synthesis of novel polycyclic cage-functionalized anion receptors. Therefore, we will adopt a “molecular architecture” approach by using different adamantane derivatives such as adamantanone, adamantanecarbaldehyde, adamantane-1,3-dicarbaldehyde, or pentacycloundecane-8,11-dione and the corresponding pyrrole derivatives. Some of the functionalized cage molecules, for example, the unnatural amino acids and hydroxy acids will be used as the templates for the synthesis of new cyclic peptides and depsipeptides. In order to design and examine the electronic and conformational behavior of the prepared peptides with chiral and nonchiral adamantane analogs, computational studies will be undertaken.