Applications of Cyclometalation Five-Membered Ring Products and Intermediates as Catalytic Agents

Abstract

The five-membered ring products and intermediates of cyclometalation reactions are very easily synthesized via donation from a hetero atom to a metal atom, which leads to the very high functionality of the product. This functionality is caused by the donation of the hetero atom and various types of metal atoms, halogen atom and other ligands such as alkanes, alkenes, alkynes, Cp, Cp*, aryl groups and heterocyclic compounds. These products have three types of catalytic applications: cyclometalation five-membered ring products as catalysts, cyclometalation five-membered ring intermediates as catalyst agents and cyclometalation five-membered ring intermediates with unconventional substrates and as catalyst actions. Because of the high functionality of these products, the applications of them have been increasing not only as the metathesis in the first and second generations of Hoveyda-Grubbs catalysts but also as in chiral reactions, cross-coupling reactions and polymerization reactions. The above cyclometalation products have been utilized for the production in many industrial fields such as pharmaceuticals, OLEDs, carbon dioxide utilizations, dye-sensitizer solar cells and sensors. We expect that these products would be used for the development of further new industrial products.