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This chapter summarizes some of the most characteristic results obtained with the use of mainly homogeneous metal complex catalysts either in the industry or in processes recommended for practical use. These are large scale processes of asymmetric synthesis of the herbicide metolachlor, synthesis of optically pure menthol with the use of chiral iridium and rhodium phosphine complexes, consideration of the synthesis of ethyl 2-hydroxybutyrate as a monomer for the preparation of biodegradable polyesters with use of heterogeneous chiral modified nickel catalyst, the manufacturing of (R)-pantolactone by means of a possible catalytic systems for enantioselective hydrogenation of ketopantolactone, and catalytic systems for the preparation of other pharmaceuticals. [ABSTRACT FROM AUTHOR]

This chapter considers the results received from enantioselective electrochemical reactions mainly from hydrogenations on metal (Pt, Ni), graphite, and Hg cathodes modified with chiral compounds (polyamino acids, alkaloids, and amino alcohols). Enantioselectivities of hydrogenation reactions were not effective, ee values did not exceed 50%, except in the cases of dehydrohalogenation and oxidation, from which optical yields reached above 90%. [ABSTRACT FROM AUTHOR]

Although the "Orito reaction", a highly effective enantioselective heterogeneous hydrogenation of 2-oxocarboxylic acid esters on Pt-alumina catalysts modified with cinchona alkaloids, was elaborated long ago, only during the 90's did a rapid growth of studies occur in this area. The reaction received strong development in experimental and theoretical aspects. Now about 300 papers have been published on the elaboration of the new catalytic systems with natural and synthetic chiral modifiers. Based on a number of alpha,beta-dicarbonyl-groups, a number of types of substrates and a number of new catalysts supported on zeolites were found. Based on detailed mechanistic studies, practical processes, such as the syntheses of the pharmaceutical, (R)-(-)-pantolactone, were accomplished with enantioselectivities above 95 %. [ABSTRACT FROM AUTHOR]

This Chapter summarizes more than 250 works of new types of metal catalysts, based on nickel and other metals including bimetals, which are active in the enantioselective heterogeneous hydrogenation of beta-keto carboxylic acid esters to beta-hydroxy carboxylic acid esters, and also are important in the production of monomers for chiral biodegradable polyesters. Cited are works mainly by groups working since the 1950's, which were published from the initial period of discovery up to the present time. Over 30 monographs and reviews on the elaboration of Ni-dissymmetric systems characterize the steps of development of this field from the first modest attempts at asymmetric hydrogenations up to the current excellent effective catalytic systems which produce optical yields of hydroxyesters up to 98% and are comparable to the effectiveness of homogeneous chiral metal-complex catalysts. But unlike them the preparation of heterogeneous metal catalysts are very simple and involve only readily available starting materials like Raney catalysts and tartaric acid as a modifier. [ABSTRACT FROM AUTHOR]

Chapter 3 presents data about enantioselective hydrogenation reactions on metal catalysts supported on chiral carriers. Discussed are palladium supported on modified silica gels, effective chiral colloidal catalysts, template catalytic systems, palladiumsilk, palladium-wool, and palladium polypeptide catalysts. [ABSTRACT FROM AUTHOR]

This chapter summarizes data about the application of chiral metal catalysts supported on optically active quartz crystals in hydrogenation and other reactions. Despite the low enantioselective efficiency of these catalysts, recent result show that almost 100% enantioselectivity results when they are involved in autocatalytic processes. [ABSTRACT FROM AUTHOR]

Chapter 1 considers the possible relationships of earthly clays and other minerals to the origin of chirality in organic molecules. Attempts to establish experimental evidence of asymmetric adsorption on clays were unsuccessful, but the search for chirality did find naturally occurring enantiomorphic crystals like quartz. Asymmetric adsorption of organic molecules on quartz crystals such as separation of racemic mixtures, like Co or Cr complexes, alcohols and other compounds, allowed for the conclusion that quartz crystals can serve as possible sources of chirality but not of homochirality. This latter conclusion results from the finding that all studied locations of quartz crystals contain equal amounts of d- and l-forms. The preparations of synthetic adsorbents such as imprinting silica gels are also considered. More than 130 references are analyzed. [ABSTRACT FROM AUTHOR]