Copper-catalyzed cross-coupling reactions

Figure 2 Recently developed ligands and bases for copper-catalyzed cross-coupling reactions. 

Introduction of the silylmethyl group into organic halides, tosylates, and epoxides is achieved by nickel, palladium-, or copper-catalyzed cross-coupling reactions. 

The copper-catalyzed cross coupling reaction of thiophenol and aryl halide was also studied by ESl-MS. In this study, reported in 2011, three anionic complexes were assigned as key intermediates, Analysis of the same mixture by positive ion mode ESI revealed only the potassium adducts of thiophenol. An anionic... 

Scheme 7. Suggested catalytic cycle for copper-catalyzed cross coupling reaction ofthiophenol and aryl halide based on detected species by ESI-MS 54. ...

Selective Nl-arylation via copper-catalyzed cross-coupling reaction may be achieved tmder ligand-free conditions or Hgand-promoted conditions. 

I 5 Metal-Catalyzed Aiylations of Nonactivated Alkyl (Pseudo) Halides via Cross-Coupling Reactions Table 5.4 Copper-catalyzed cross-coupling reactions between unactivated alkyl halides and aryl metal reagents. copper catalyst... 

CO insertion prior to the transmetallation step. The mechanism of nickel-catalyzed coupling reactions is less established. Early studies indicated that homocoupling processes occur by oxidative addition through radical intermediates and possible intermediacy of Ni(I) and Ni(III) complexes. The copper-catalyzed cross-coupling reactions likely occur by transmetallation prior to oxidiative addition of the aryl halide. Iron-catalyzed reactions likely occur by low-valent, even sub-valent, species. 

Copper-Catalyzed Cross-Coupling Reactions of Oiganozinc Reagents... 

Some of these drawbacks have been overcome by the recent developments in copper-catalyzed cross-coupling reactions. Buchwald and coworkers reported the coupling of variety of phenols with aryl bromides in the presence of Cs COj (Scheme 20.34) [89]. The less reactive phenols required an equivalent amount of 1-naphthoic acid and molecular sieves to facilitate the transformation. Under these conditions, the reaction of unactivated aryl halides and less reactive or hindered phenols can be achieved. 

Use of IL in other reaction 1-Alkyl-3-methylimidazolium cation-based ILs were used for A-teri-butyloxycarbonylation of amines with excellent chemose-lectivity [32]. 1,3-dialkylimidazolitrm ILs such as [bmim][PFg]. [bmTr][PFg] and [bmTr][NTf2] were reported for reaction media for the Baylis-Hillman reaction [33]. 1-butyl-3-methylimidazohrrm-based IL [bmim][NTf2] is used as solvent for a-methylenations of carbonyl compotmds [34]. M. L. Kantam et al. described copper-catalyzed cross-coupling reaction of arylboronic acids with sulfonic acid for alkylaryl and diaryl sulfones using IL [35]. 

Scheme 4.32 Synthetic model for the study of the copper-catalyzed cross-coupling reaction...

In order to increase the yield of the copper-catalyzed cross-coupling reaction, the synthesis of a less bulky lactam is proposed (Scheme 5.7). This new lactone-lactama XIX is characterized by a less steric hindrace around the quaternary center. 

Vinyl ethers can be generated by a copper-catalyzed cross-coupling reaction between alcohols and vinyl halides under air [105]... 

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