Ruthenium complexes organic transformations

As one might expect, the fairly large number of transition metals has resulted in a very large number of organic transformations. Virtually all of the transition metals have been used to create new carbon-carbon bonds in various reactions. However, two metals in particular have had tire greatest impact on preparative organic chemistry. The use of palladium and ruthenium complexes... 

Ruthenium catalysts found many applications in C-C bond formation reactions (selected reviews [157-161]). Ruthenium occurs mostly in oxidation states +2 and +3, but lower as well as higher oxidation states can easily be reached. Thus ruthenium compounds are frequently used in oxidative transformations proceeding by either single or two electron transfer pathways (selected reviews [162-164]). It has long been known that ruthenium complexes can be used for the photoactivation of organic molecules (selected reviews [165, 166]). Ruthenium complexes are applied as catalysts in controlled or living radical polymerizations [167-169]. 

Abstract Ruthenium-catalyzed carbonylation reactions are described. The purpose of this chapter is to show how ruthenium complexes as catalysts are important in the recent development of carbonylation reactions. This review does not present a complete, historical coverage of ruthenium-catalyzed carbonylation reactions,but presents the most significant developments of the last 10 years. The emphasis is on novel and synthetic transformations of genuine value to organic chemists. Especially, this review will focus on carbonylative cycloadditions and carbonylation of C-H bonds. The review is generally organized according to the nature of the reaction. 

The chemistry of ruthenium complexes incorporating edta, or related ligands such as pac, is generally based on substitution reactions of the water ligand present in the coordination sphere of the metal. The catalytic properties of these complexes in various organic transformations have been exploited, including electrocatalytic studies. ... 

Ruthenium W-Heterocyclic Carbene Complexes for the Catalysis of Nonmetathesis Organic Transformations... 

In continuation of our research on design of novel catalysts for selective organic transformations, we have synthesized more flexible, expanded PNN-type pincer ruthenium complexes (18-20). However, only modest catalytic activity and selectivity was observed with these bridged-bipyridine-based PNN-Ru(II) complexes in amide hydrogenation (25-65% yields) and other reactions [70]. This is likely a result of cyclometalation of the active species 21 and 22, which is detrimental to the catalysis (Scheme 8 Fig. 10). The low stability of the expected dearomatized complex (20a) formed by deprotonation of 20 was also detrimental to catalysis. 

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