Industrial applications asymmetric catalysis

Industrial applications inclnde the production of petrochemicals, fine chemicals and pharmacenticals (particnlarly throngh asymmetric catalysis), hydrometallurgy, and waste-treatment processes. Many life processes are based on metallo-enzyme systems that catalyse redox and acid-base reactions. 

For the production of chemicals, food additives and pharmaceutical products, homogeneous catalysis offers some attractive features such as a high selectivity and activity, e.g. in asymmetric synthesis. However, since most homogeneous catalysts are relatively expensive, their current industrial application is limited [3]. On the other hand, heterogeneous catalysts can easily be separated from the products and can be recycled efficiently. Membrane separations with emphasis on nanofil-tration and ultrafiltration will allow for a similar recyclability of homogeneous catalysts, which is important both from an environmental as well as a commercial... 

Arylation, olefins, 187, 190 Arylketimines, iridium hydrogenation, 83 Arylpropanoic acid, Grignard coupling, 190 Aspartame, 8, 27 Asymmetric catalysis characteristics, 11 chiral metal complexes, 122 covalently bound intermediates, 323 electrochemistry, 342 hydrogen-bonded associates, 328 industrial applications, 8, 357 optically active compounds, 2 phase-transfer reactions, 333 photochemistry, 341 polymerization, 174, 332 purely organic compounds, 323 see also specific complexes Asymmetric induction, 71, 155 Attractive interaction, 196, 216 Autoinduction, 330 Axial chirality, 18 Aza-Diels-Alder reaction, 220 Azetidinone, 44, 80 Aziridination, olefins, 207... 

SCHEME 5. Industrial applications of homogeneous asymmetric catalysis. 

We have been gratified to see that the Comprehensive Asymmetric Catalysis three volume set has been received with enthusiasm by the chemical community since its publication in 1999. As was easily anticipated, advances in asymmetric catalysis have continued at an explosive pace since then. Recognition of the impact of this field on chemistry has been evidenced both in practical terms by the application of asymmetric catalytic methods in a variety of new laboratory and industrial contexts, and quite visibly through the lofty recognition of to three of the pioneers of the field in the 2001 Nobel Prize. 

During the past decade, metal-catalyzed asymmetric reactions have become one of the indispensable synthetic methodologies in academic and industrial fields. The asymmetric isomerization of allylamine to an optically active enamine is a typical example of the successful application of basic research to an industrial process. We believe that Takasago s successful development of large-scale asymmetric catalysis will have a great impact on both synthetic chemistry and the fine chemical industries. The Rh-BINAP catalysts, though very expensive, have become one of the cheapest catalysts in the chemical industry through extensive process development. 

OECD Report, The Application of Biotechnology to Industrial Sustainability, 2001, http //www. Loecd.org/publications/e-book/9301061e.pdf Panke, S., Held, M., and Wubbolts, M. Curr. Op. Biotech. 2004, 35, 272-279 Plomp, P., de Boer, L., van Rooijen, R., and Meima, R. 2004, Patent WO 04/030468 Pochlauer, P., Skranc, W., and Wubbolts, M. The large-scale biocatalytic synthesis of enantiopure cyanohydrins in Asymmetric Catalysis on Industrial Scale, H. U. Blaser, and E. Schmidt (Eds.), Wiley-VCH, Weinheim, 2004,151-164 Schmid, A., Dordick, J. S., Hauer, B., Kiener, A., Wubbolts, M., and Wifholt, B. Nature,... 

Conceptually new multifunctional asymmetric two-center catalysts, such as the Ln-BINOL derivative, LnMB, AMB, and GaMB have been developed. These catalysts function both as Brpnsted bases and as Lewis acids, making possible various catalytic, asymmetric reactions in a manner analogous to enzyme catalysis. Several such catalytic asymmetric reactions are now being investigated for potential industrial applications. Recently, the catalytic enantioselective opening of meso epoxides with thiols in the presence of a heterobimetallic complex has... 

Reaction 9.1 has been extensively studied to establish the mechanism of asymmetric hydrogenation. The catalytic cycle proposed for the asymmetric hydrogenation of the methyl ester of a-acetamido cinamic acid with 9.14 as the precatalyst is shown in Fig. 9.3. As mentioned earlier, this reaction is one of the early examples of industrial applications of asymmetric catalysis for the manufacture of L-DOPA (see Table 1.1). 

The purpose of this chapter is to inspire future applications of asymmetric catalysis in industry. As a didactic example, we feature the design and development of a unique class of chiral diphosphine ligands that are useful in asymmetric chemocatalysis. We illustrate the availing nature of these ligands in asymmetric catalytic hydrogenation reactions. As will become apparent, effective ligand design is a quintessential component in the cultivation of viable asymmetric catalytic processes. 

In the area of polymerizations new ligand systems have dramatically improved catalyst performance. The developed organometallic complexes might also find widespread application in organic synthesis. As an example metallocene catalysts offer new opportunities in asymmetric catalysis " after having proven to be industrially viable for olefin polymerization ll... 

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