Catalysis continued heterocycles

Heterocyclic compounds are indispensable in recent far-reaching developments in the material and biological sciences because they can be used as a substructure in functional materials, agrochemicals, and pharmaceuticals. Transition-metal catalysis continues to be a fruitful source of new methods for the synthesis of heterocyclic compounds, since transition-metal catalysts can be used to construct complex structures directly from easily accessible starting materials under neutral and mild reaction conditions. The cycloaddition of unsaturated molecules is one of the most straightforward and atom-economical reactions for constructing substituted heterocyclic compounds [20]. 

Following the introduction to this volume provided herein, the following authors will continue the discussion of N-heterocyclic carbenes in this volume. Peris will discuss routes to NHC complexes, a prerequisite for doing catalysis. First and foremost, palladium catalysis has benefited from the use of NHC. The unique properties of NHC allow their use in oxidation catal-... 

Ruthenium iV-heterocyclic carbene (NHC) complexes have been at the forefront of the development of NHCs into the ubiquitous ligands now found in organometallic catalysis. Prior to 2005, their impact was primarily in metathesis chemistry [1], and our review of the literature at that time revealed a relatively limited number of applications outside of this area [2]. This updated chapter reveals quite clearly not only a continued growth in interest in Ru-NHC catalysis, but more obviously, a very significant diversification of catalytic applications. Other reviews on, or containing aspects of, Ru-NHC-catalyzed chemistry have appeared recently in the literature [3-8] or in other textbooks on NHCs [9-llj. 

In recent years, research in the field of Rh catalysis has resulted in the development of numerous transformations that provide various nitrogen heterocycles. Most of the transformations result in the formation of a C-N bond with good to excellent yields, in addition to good stereocontrol. Despite the many developments that have been made in this arena, new findings are being reported with greater frequency. This research area will potentially remain a fruitful discipline for many years to come. In particular, the development of new Rh catalysts and Rh-catalyzed reactions will likely take a lead role, with more attention on the scope and application of the transformations. In addition, studies on the catalytic reaction mechanisms to understand the nature of the reactions will continue for some period. 

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