ORGN 184

This molecular BR topology provides a unique symmetrical, nanoscale three-dimensional scaffold onto which unique features can be embedded at will. The significance of this research is to introduce a further level of sophistication structure-wise into the metal containing BRs via the construction (Box) of hexasubstituted borromeates. Two orthogonal approaches have been investigated, namely Pre-Assembly Modification – which involves the incorporation of the desired functionality on the incipient tridentate ligand, followed by subsequent assembly of the rings via metal template-directed synthesis, and Post-Assembly Modification – which first of all involves the synthesis of Borromeates with pendant reactive groups attached to the incipient tridentate ligand prior to assembly, then modification of the periphery via the introduction of a new functional group. Herein, we show the efficient convergent formation of both hexaolefinic and hexa-p-tolylpentenyloxy Borromeates. The latter involved the application of olefin cross metathesis (OXM) in a pre-assembly fashion to incorporate p-tolyl-pentenyloxy substituents onto the 4-position of an endo-diiminopyridyl ligand which lead to the successful convergent synthesis of hexa-p-tolyl-pentenyloxy functionalized Borromeates. For comparison, in post-assembly terms, efforts were made to incorporate six styrenic substrates to a pre-assembled olefin-modified Borromeate core employing olefin cross metathesis. The results conclude that the making of hexasubstituted Borromeates divergently, is still an open challenge, as demonstrated by the application of ruthenium-catalyzed OXM to a pre-assembled hexaolefinic Borromeate core.