Oxidation Using Ruthenium Catalysts

Abstract

Among the catalysts which have potential for use in selective oxidations, ruthenium takes a special position owing to its versatility. Ruthenium can catalyse numerous oxidative transformations: the oxidation of alkanes, the cleavage of double bonds, the asymmetric epoxidation of alkenes, the oxidation of alcohols and ethers and the oxidation of amines and amides. In the field of alcohol, ether and amide oxidation, ruthenium-based catalysts certainly belong to the state of the art in their field and bear great potential for application in fine chemical synthesis. A range of oxidation states can be encountered in the various ruthenium intermediates which are responsible for the respective transformations: Ru(VIII) as in ruthenium tetroxide, Ru(VII) as in perruthenates, Ru(IV)–Ru(VI) in oxo-intermediates and Ru(II) can be applied in (de)hydrogenations. Details regarding the various oxidation mechanisms are discussed. In this chapter the focus is on green technologies and therefore examples of ruthenium-catalysed oxidations using environmentally benign oxidants are emphasized.