Cross transition metal-catalysis

Transition metal-catalysed reactions have emerged as powerful tools for carbon-carbon (C-C) bond formation [1], Cross-coupling reactions (Suzuki-Miyaura, Mizoroki-Heck, Stille, etc.) are recognised to be extremely reliable, robust and versatile. However, some other catalysed arylation reactions have been studied and have been reported to be very efficient [2]. In recent years, A -heterocyclic carbenes (NHC) have been extensively studied and their use as ligands for transition-metal catalysis has allowed for the significant improvement of many reactions [3]. This chapter highlights the use of NHC-bearing complexes in those arylation reactions. 

Keywords Carbon-carbon bond formation Cross-coupling reaction Organobismuth compounds Transition-metal catalysis... 

The application of transition metal catalysis provided new opportunities to introduce diverse functionality to the diazepine ring system. Iron-catalyzed cross-coupling of Grignard reagents with the imidoyl chloride 40 provided a convenient and efficient method for substituting the heterocyclic ring (Scheme 9) <20060L1771>. 

Negishi, E., Van Horn, D. E. Selective carbon-carbon bond formation via transition metal catalysis. 4. A novel approach to cross-coupling exemplified by the nickel-catalyzed reaction of alkenylzirconium derivatives with aryl halides. J. Am. Chem. Soc. 1977, 99, 3168-3170. 

Iron, cobalt and manganese are effective catalysts for cross coupling and other reactions. They were studied in the very early days of transition-metal catalysis and are now being resurrected." ... 

From C-H to C-C Bonds Cross-Dehydrogenative-Coupling 27 Renewable Resources for Biorefineries 28 Transition Metal Catalysis in Aerobic Alcohol Oxidation 29 Green Materials from Plant Oils... 

Although cobalt catalysis is somewhat less developed compared to other transition metal catalysis for cross-coupUngs, but has shown rather unconventional, novel reactivity profiles [50]. For example, Oshima reported a cobalt-catalyzed tandem radical cyclization/cross-coupling reaction between an aryl Grignard reagent and an alkyl halide bearing an (o-alkenyl group (Equation 5.44) [51]. 

Pd-catalyzed site-selective cross-coupling reactions demonstrate the influential role of ligands in transition metal catalysis. The reactions described in this review discuss efficient approaches to introduce various substituents at specific halo-substituted posititMis (Ml (hetero)aromatic compounds. The commercial availability of a variety of dihalo-substituted starting materials makes site-selective crosscoupling reactions practical for the rapid production of diverse (hetero)arenes with multiple substituents. In all examples described here, the reactions proceeded successfully only on substrates containing hetero atoms, and this field of chemistry aims to include substrates without hetero atoms in the substrate scope. 

Over the last decade, the copper-mediated or copper-catalyzed C-H functionalization has been developed rapidly and greatly by significant efforts of many researchers, and cheap and abundant copper salts now can replace, to some extent, precedented noble transition metal catalysts such as Pd, Rh, and Ru. Moreover, some unique features of copper salts and complexes are observed. The intermolecular dehydrogenative cross-couplings mentioned in this chapter are such good examples, and they are otherwise challenging even under known noble transition metal catalysis. However, there is still a large room for further... 

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