Cross-coupling reactions involving

Chromans have been obtained by the Pd-catalysed intramolecular cross coupling reaction involving aryl halides containing an ortto-hydroxyalkyl substituent <96JA10333>. 

These interesting biological properties have fueled the development of new synthetic methods aimed at rapidly assembling these simple compounds and analogues thereof. Within this context, Larock s three-component cross-coupling reaction involving halo-pyridines, dienes and amines stands as a powerful method as it... 

The application of Heck coupling polycondensation is not limited to the synthesis of poly(arylene vinylene)s via the alkenylation of haloarenes in simple monomer systems but includes a variety of self- and cross-coupling reactions involving reactants with various functionalities. For instance, the polycondensation of diiodoarene with bis(acrylamido)arene by the Pd(OOCCH3)2—P (o-C6H4—CH3)3 catalyst yields respective aromatic polycinnamamide [106] ... 

In the cross-coupling reactions involving organolead triacylate reagents, the lead compound reacts as a carbocationic equivalent. An elusive covalent substrate-lead intermediate undergoes a reductive elimination at the lead center (Scheme 6). 

The Stille reaction in its traditional form is thus now well established, and finds many uses in preparative chemistry. The use of other transition metals in cross-coupling reactions involving organotins is still in its infancy, however, and it seems very worthwhile to investigate this aspect of tin chemistry further, as it is likely to provide other useful weapons for the armory of that insatiable beast, the synthetic organic chemist. 

The catalytic cycle for the Suzuki cross-coupling reaction involves an oxidative addition (to form RPd(II)X)-transmetalation-reductive elimination sequence. The transmeta-lation between the RPd(lI)X intermediate and the organoboron reagent does not occur readily until a base, such as sodium or potassium carbonate, hydroxide or alkoxide, is present in the reaction mixture. The role of the base can be rationalized by its coordination with the boron to form the corresponding ate-complex A, thereby enhancing the nucleophilicity of the organic group, which facilitates its transfer to palladium. Also, the base R O may activate the palladium by formation of R-Pd-OR from R-Pd-X. 

Various transition metals (Pd, Rh, Ru, Cu, Fe, etc.) have been shown to be effective for cross-coupling reactions involving C-H bond activation in recent years (for copper, see [33-38] for iron, see [39, 40]). Pd(II) salts have emerged as the preferred catalysts to promote the C-H bond cleavage in catalytic direct arylation reactions. This process can be classified into two parts, the organometallic reagent is replaced by a simple arene in one case, and the aryl halide is replaced by a simple arene in another (Scheme 4). 

The development of C-H activation for cross-coupling reactions has been advanced rapidly. Extensive efforts have been devoted to the mechanistic studies in this field to shed light on the mechanism. The use of oxygen or air as sole oxidant has been successfully realized in a palladium-catalyzed cross-coupling reaction involving C-H activation. We have the right to believe that palladium-catalyzed double C-H activation would be a good alternative for the synthesis of biaryls. With further improvements in catalyst turnover, selectivity, and oxidant, the method should ultimately be able to find industrial applications. 

Palladium-catalysed cross-coupling reactions involving pyrroles Banwell, M. G., Goodwin, T. E., Ng, S., Smith, J. A. and Wong, D. J., Eur. J. 

Figure 7.1 Cross-coupling reactions involving Grignard reagents.

Figure 7.2 Cross-coupling reactions involving organoindium compounds.

Chapter 5 details conditions for performing the Heck reaction (including one asymmetric version) while Chapter 6 describes how Sonogashira reactions can be conducted successfully. (The conditions of Plenio and Luo can be used to perform Heck and/or Suzuki reactions). In Chapter 7 cross-coupling reactions involving... 

Biaryls Unsymmetrical biaryls are formed from a cross-coupling reaction involving Arl and tetrabutylammonium triaryldifluorosilicates. The catalyst is bis(allylpalladium chloride). 

Very recently a further mechanistic investigation of the vinyl cross-coupling reactions, involving oxidative addition and reductive elimination of a vinyl triflate with Pt(0), was... 

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