Carbon copper-catalyzed cross-coupling reactions

Tributylstannyl)-3-cyclobutene-1,2-diones and 4-methyl-3-(tributylstan-nyl)-3-cyclobutene-l,2-dione 2-ethylene acetals undergo the palladium/copper-catalyzed cross coupling with acyl halides, and palladium-catalyzed carbon-ylative cross coupling with aryl/heteroaryl iodides [45]. The coupling reaction of alkenyl (phenyl )iodonium triflates is also performed by a palladium/copper catalyst [46],... 

The chiral Diels-Alder adduct 19 is a versatile intermediate for the synthesis of many chiral bicyclo[2.2.1]heptadienes, because the tri-n-butylstannyl group can be replaced by halogen or a wide variety of carbon appendages, the latter by use of either copper-mediated or palladium-catalyzed cross-coupling reactions. For example, as shown in Eq. (34), reaction of 19 with A-iodosuccinimide produced the iodo aldehyde 12 in 92 % yield. Coupling of 12 with ( )-/ -styryl-tri-n-butylstannane and either 1.5 equiv. copper(I) 2-thiophenecarboxylate (CuTC) or catalytic PdCl2(CH3CN)2 afforded the triene aldehyde 20 [34]. 

During the past few decades, transition metal-catalyzed cross-coupling reactions have become a powerful tool for the construction of C—C and C-heteroatom bonds [1]. This strategy allows the conceptually simple and yet powerful and reliable approach for synthesizing structurally complex pharmaceuticals and biologically active molecules. The two most vastly used transition metal catalysts in carbon-heteroatom bond formation are palladium (mainly depends on its ancillary ligands) and copper (depends on the optimization of the catalytic system as a whole copper source, solvent, base, concentrations, etc.). Besides, considerable developments have also been made with other transition metal catalysts such as nickel, iron, etc. 

Carbon-carbon bond-forming reactions are one of the most basic, but important, transformations in organic chemistry. In addition to conventional organic reactions, the use of transition metal-catalyzed reactions to construct new carbon-carbon bonds has also been a topic of great interest. Such transformations to create chiral molecules enantioselectively is therefore very valuable. While various carbon-carbon bond-forming asymmetric catalyses have been described in the literature, this chapter focuses mainly on the asymmetric 1,4-addition reactions under copper or rhodium catalysis and on the asymmetric cross-coupling reactions catalyzed by nickel or palladium complexes. 

Selective cross-coupling reactions between C(sp ) and C(5p ) centers had been one of the most difficult tasks in carbon-carbon bond synthesis until the early 1970s, when it was first reported that iron, nickel, palladium and copper - catalysts are extremely effective for cross-coupling of Grignard reagents with organic halides. Now, nearly 20 years later, transition metal catalyz cross-coupling has become the reaction of first choice for this purpose. 

Several copper-catalyzed 7 -arylation reactions of imidazole have been published. The coupling of arylboronic acids with imidazole in the presence of binuclear bis-p,-hydroxy copper (11) complexes in air has been carried out at ambient temperature without the need for base <04TL7659>. A variety of A -arylimidazoles were prepared in excellent yields through the cross-coupling of arylboronic acids with imidazole in methanol or water with copper(I) chloride <04CC188>. Copper(II) oxide-coated nanoparticles were used catalytically in the Ullmann coupling of imidazole with various aryl chlorides with cesium carbonate in dimethyl sulfoxide <04CC778>. 

Copper-Catalyzed Carbon-Nitrogen Cross-Coupling Reactions... 

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