Development of catalyst-based processes is critical for creating sustainable technology. One such class of reactions, olefin-metathesis mediated by transition metal complexes has recently emerged as a vital tool for organic synthesis. Besides the creation of organic polymers through ring-opening, a new methodology involving tandem synthesis offers a facile route to macrocyclic systems, which now comprise many new pharmaceutical agents. Ruthenium-alkylidene complexes of the Grubbs and Hoydeia variety perform efficient metathesis for a diverse variety of substrates with high functional group tolerance. However, are three main problems encountered with olefin metathesis by these types of complexes, namely, low-yielding asymmetric synthesis, unpredictable cycloisomerization, and inefficient operation under aqueous conditions. The latter has become necessary in order to prepare high molecular weight biological targets. To address these problems, a Ru-based catalyst based on the N,N-chelating ligand, beta-diketiminate, is proposed. Advantages of this ligand include easy and high yielding preparative procedures with flexibility to attach a variety of substituents, including water-soluble functionalities. Furthermore, possibilities exist to create a chiral ligand for promoting asymmetric reactions. Anchoring of the catalyst through attachment of the ligand framework to a solid state support would facilitate high-throughput screening of substrates and assist in the rapid identification of problematic cases. The conditions which promote cycloisomerization over olefin metathesis will also be investigated. Structural data from single crystal X-ray diffraction studies combined with models calculated by the combination of density functional theory and molecular mechanics will help to identity key mechanistic features related to olefin metathesis. These findings, will in turn, be used to adjust and fine-tune the properties of ligand and hence the activity of the catalyst.
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