Organic catalysis

Indeed, these reactions proceed at 25 °C in ethanol-aqueous media in the absence of transition metal catalysts. The ease with which P-H bonds in primary phosphines can be converted to P-C bonds, as shown in Schemes 9 and 10, demonstrates the importance of primary phosphines in the design and development of novel organophosphorus compounds. In particular, functionalized hydroxymethyl phosphines have become ubiquitous in the development of water-soluble transition metal/organometallic compounds for potential applications in biphasic aqueous-organic catalysis and also in transition metal based pharmaceutical development [53-62]. Extensive investigations on the coordination chemistry of hydroxymethyl phosphines have demonstrated unique stereospe-cific and kinetic propensity of this class of water-soluble phosphines [53-62]. Representative examples outlined in Fig. 4, depict bidentate and multidentate coordination modes and the unique kinetic propensity to stabilize various oxidation states of metal centers, such as Re( V), Rh(III), Pt(II) and Au(I), in aqueous media [53 - 62]. Therefore, the importance of functionalized primary phosphines in the development of multidentate water-soluble phosphines cannot be overemphasized. 

Keywords Organometallic Nanoparticles Surface chemistry Self-organization Catalysis... 

Throughout this book a major stress is on catalysis in organisms. Catalysis is confined to non-metals and metal ions of attacking power, either as Lewis acids or in oxidation/reduction and this excludes the simplest ions such as Na+, K+ and Ca2+ (and Cl- among anions). The transition metal ions and zinc are the most available powerful catalysts. The metals in a transition series are known to have selective binding properties, exchange rates and oxidation/reduction states, which can be put to use in catalysis in quite different ways (Table 2.13). It is noticeable that especially the complexes of metal elements... 

University of Liege, Laboratory of Macromolecular Chemistry and Organic Catalysis, Sart Tilman, 4000 Liege, Belgium... 

Horvath recognized that SAPC solved the problem posed by the solubility of lypophilic substrates in aqueous biphasic catalysis with water-soluble homogeneous catalysts. He compared biphasic aqueous-organic catalysis with SAPC, in order to clarify whether in SAPC the catalyst remained dissolved in the... 

Eidus applied this name to components which do not participate in the stoichiometry equation of a catalytic process, but whose presence is, nevertheless, important (133). Such an effect of hydrogen has been reported to be rather general in organic catalysis (134). Metal-carbon ensembles may serve as sites for hydrogen transfer (134a). 

Among the most widely recognized areas of organic catalysis in the modern have been the seminal studies of Yang, - ... 

While the studies outlined in Eqs. (11.1)-(11.8) summarize the most important frontiers for metal-free synthesis, they also highhght a common limitation for the organocatalysis field. To date, there remain relatively few (less than 10) activation mechanisms that have been established to be amenable to organic catalysis. Accordingly, a primary objective for the advancement of the field of asymmetric organocatalysis has been the design and/or development of concepts that enable organic substrates to function as catalysts for a wide variety of new and established reactions. 

Chemical Research Center, Institute of Surface Chemistry and Catalysis, Department of Organic Catalysis, 1025 Budapest, Pusztaszeri tit 59-67Hungary... 

Another example of organic catalysis was reported (7. Am. Chem. Soc. 2004, /26,450) by Benjamin List of the Max Planck Institute, Mulheim. The amino acid 8 cyclizes 7 to 9 efficiently and with high enantioselectivity. This is particularly remarkable given the ease with which 9 would be expected to racemize under acidic or alkaline conditions. 

The Effects of Ionizing Radiation on Solid Catalysts Ellison H. Taylor Organic Catalysis over Crystalline Aluminosilicates P. B. Venuto and P. S. Landis On the Transition Metal-Catalyzed Reactions of Norbornadiene and the Concept of tr Complex Multicenter Processes G. N. SCHRAUZER... 

Department of Organic Chemistry and Organic Catalysis Research Group of the Hungarian Academy of Sciences, Jozsef Attila University, Dorn ter 8, H-6720 Szeged, Hungary... 

The main emphasis has so far been placed on metal-containing catalysts, both in the field of dendritic catalysis and in organic catalysis in general. However, the current trend is increasingly towards catalysis with purely organic compounds. A number of example of such metal-free - and dendritic - catalysts,... 

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