Asymmetric synthesis with biocatalyst has become an increasingly interesting and cost effective manufacturing process in fine chemicals, pharmaceuticals, and agrochemical intermediates. Enoate reductases from the Old Yellow Enzyme family offer high substrate efficiency, region, stereo-, and enantioselectivity in the catalyzed biotransformations. Asymmetric reduction of activated C=C bond is one of the most widely applied synthetic tools for the potential to generate up to two stereogenic centers in one step reaction. The thesis contributed to the development and characterization of the Old Yellow Enzyme family members including NRSal from Salmonella typhimurium, YersER from Yersinia bercoviei, KYE1 from Kluyveromyces lactis, and XenA from Pseudomonas putida. We explored the possible new chemistry, gathered further understanding of enzymes functionality and biochemistry, evaluated parameters such as enzyme stability, productivity, and selectivity, and improved enzyme specificity through computational guided protein engineering method. In overall, the increasing knowledge about this Old Yellow Enzyme family together with recent advances in biotechnology renders the enoate reductases a tool of choice for industrial applications.

At the threshold of the 21st centry, a new set of challenges is defined by the need to develop sustainable means of preparing chemical commodities demanded by society. Hence, such concepts as atom economy, step economy, and 'green chemistry' have become the requirements for the development of synthetic reactions. Hydrogenation is one of the most powerful catalytic methods which successfully satisfy the stated requirements of modern chemistry. Accordingly, catalytic hydrogenation has been tremendously utilized in industrial settings. The profound impact of hydrogenation portended a powerful approach to reductive carbon-carbon bond formation under hydrogenation conditions, resulting in the discovery of the Fischer-Tropsch process and hydroformylation. However, since this discovery, processes have restricted to the incorporation of a single carbon monoxide unit. Even though there are a few seminal contributions, systematic efforts toward the development of hydrogen-mediated carboncarbon bond forming processes beyond hydroformylation have been absent from the literature. In an exciting advance, the Krische group has shown that it is possible to reductively couple two or more organic molecules simply through their exposure to gaseous hydrogen in the presence of a metal catalyst. This finding has led to the development of a broad, new family of hydrogen-mediated C-C bond formation. Herein, related to hydrogen-mediated C-C bond formation, the overview of metal catalyzed intermolecular reductive coupling in the presence of reducing agents such as borane, silane, alane, metal, and hydrogen is presented. Chapter 2 describes systematic approaches to the development of hydrogen-mediated C-C bond formation and successful preliminary results achieved by our research group. Chapters 3 and 4 will describe the further extension of these hydrogen-mediated C-C bond formations including (1) hydrogen-mediated reductive couplings of conjugated alkynes with iminoacetates, (2) hydrogen-mediated reductive couplings of 1,3-enynes with [alpha]-ketoesters, and (3) hydrogen-mediated multicomponent reductive couplings. The development of catalytic systems for the nucleophilic activation of enones using phosphine catalysts has received attractive attention. Recently, an intramolecular variant of the Rauhut-Currier reaction was developed in our lab. To further extend nucleophilic phosphine catalysis, we have sought to develop new catalytic methodology via phosphine conjugate addition. Chapter 5 describes two new methodologies related to their area: (1) catalytic cycloallylation via nucleophilic phosphine catalysis and (2) allylic amination of Morita-Baylis-Hillman acetates. / text

Hydrogen gas is the cleanest and most cost-effective reductant available to mankind, and the use of hydrogen gas in catalytic hydrogenation reactions is one of the oldest and most utilized organic reactions. Although catalytic hydrogenation has been practiced in industry on enormous scale, the use of hydrogen gas as a terminal reductant in C-C bond forming reactions has been limited to processes involving the migratory insertion of carbon monoxide such as: alkene hydroformylation and the Fischer-Tropsch reaction. A significant advance to the field of synthetic organic chemistry would be the expansion of C-C bond forming reactions beyond reductive coupling via carbon monoxide insertion. Herein, related metal catalyzed reductive couplings to [alpha],[beta]-unsaturated compounds in the presence of reducing agents such as: silane, borane, and hydrogen are reviewed. The following chapters discuss the development of hydrogen-mediated reductive aldol and Mannich reactions. The results from this body of work clearly demonstrate that hydrogen-mediated C-C bond forming reactions are emerging as a powerful tool for synthetic chemists.

The kinetics of incongruent reduction between sapphire and oxygen-controlled Mg-Al melts was studied by measuring spinel-layer thickness, sample-weight change and sample-thickness change as a function of time at various temperatures. To eliminate the crucible contamination caused by impurities in commercial MgO crucibles, self-made high-purity MgO crucibles were achieved by gelcasting method, which is an attractive ceramic-forming technique for making high-purity ceramic parts. The oxygen-controlled alloys were obtained by the three-phase-equilibrium experiments at various temperatures. To avoid MgO formation, the oxygen-controlled alloys prepared at relatively lower temperatures were used for incongruent reaction at relatively higher temperatures. That is to say, the oxygen-controlled alloys prepared at 900°C, 1000°C, and 1100°C were used for spinel formation at 1000°C, 1100°C, and 1200°C, respectively. The experiments were conducted in a vertical furnace, and sapphire wafers were hung vertically in high-purity MgO crucibles so that the natural convection induced by the density change in the melt could be investigated. Experimental results obtained at 1000°C, 1100°C, and 1200°C showed that the spinel layer thickness on two kinds of sapphire wafers, namely {0001} and , followed orientation-independent parabolic kinetics, indicating the diffusion in spinel was one of the rate-limiting steps. In addition, the spinel layer thickness was not a function of position. The results of sample-thickness- change measurements also indicated that the effect of natural convection could be neglected. XPS, XRD, and TEM were also employed to characterize some samples in this study. Based on a simple model where the diffusion in spinel was the only rate-limiting step, the governing partial differential equations for diffusion and fluid dynamics were solved by the finite element method. The calculated theoretical parabolic constants at various temperatures were compared with these experimental results, and a good agreement was obtained. Some preliminary studies were also made on the morphologies of spinel particles at the nucleation stage. It was found that the triangular {111} faces of spinel particles were parallel to the surface of {0001} sapphire substrate. The product shape was consistent with the tetrahedron composed of {111} faces. The morphology of spinel particles on a sapphire substrate was more complicated in that the triangular {111} faces of spinel had to be inclined at a certain angle to the substrate in order to maintain the orientation relationship.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2009. / Includes bibliographical references.

Thesis (doctoral)--Technische Universiteit Delft, 2002. / Vita. Includes bibliographical references.

Thesis (M.S.)--Chemical Engineering, Georgia Institute of Technology, 2005. / Empie, Jeff, Committee Chair ; Banerjee, Sujit, Committee Member ; Deng, Yulin, Committee Member. Includes bibliographical references.

Thesis (doctoral)--Technische Universiteit Delft, 2002. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2009. / Additional advisors: Heng Ban, Chih-Hsiung Cheng, Thomas K. Gale, Melinda M. Lalor. Description based on contents viewed June 3, 2009; title from PDF t.p. Includes bibliographical references (p. 113-123).