In the last decade there have been numerous advances in the area of rhodium-catalyzed hydroformylation, such as highly selective catalysts of industrial importance, new insights into mechanisms of the reaction, very selective asymmetric catalysts, in situ characterization and application to organic synthesis. The views on hydroformylation which still prevail in the current textbooks have become obsolete in several respects. Therefore, it was felt timely to collect these advances in a book. The book contains a series of chapters discussing several rhodium systems arranged according to ligand type, including asymmetric ligands, a chapter on applications in organic chemistry, a chapter on modern processes and separations, and a chapter on catalyst preparation and laboratory techniques. This book concentrates on highlights, rather than a concise review mentioning all articles in just one line. The book aims at an audience of advanced students, experts in the field, and scientists from related fields. The didactic approach also makes it useful as a guide for an advanced course.

An essential reference to the highly effective reactions applied to modern organic synthesis Rhodium complexes are one of the most important transition metals for organic synthesis due to their ability to catalyze a variety of useful transformations. Rhodium Catalysis in Organic Synthesis explores the most recent progress and new developments in the field of catalytic cyclization reactions using rhodium(I) complexes and catalytic carbon-hydrogen bond activation reactions using rhodium(II) and rhodium(III) complexes. Edited by a noted expert in the field with contributions from a panel of leading international scientists, Rhodium Catalysis in Organic Synthesis presents the essential information in one comprehensive volume. Designed to be an accessible resource, the book is arranged by different reaction types. All the chapters provide insight into each transformation and include information on the history, selectivity, scope, mechanism, and application. In addition, the chapters offer a summary and outlook of each transformation. This important resource: -Offers a comprehensive review of how rhodium complexes catalyze a variety of highly useful reactions for organic synthesis (e.g. coupling reactions, CH-bond functionalization, hydroformylation, cyclization reactions and others) -Includes information on the most recent developments that contain a range of new, efficient, elegant, reliable and useful reactions -Presents a volume edited by one of the international leading scientists working in the field today -Contains the information that can be applied by researchers in academia and also professionals in pharmaceutical, agrochemical and fine chemical companies Written for academics and synthetic chemists working with organometallics, Rhodium Catalysis in Organic Synthesis contains the most recent information available on the developments and applications in the field of catalytic cyclization reactions using rhodium complexes.

Rhodium has proven to be an extremely useful metal due to its ability to catalyze an array of synthetic transformations, with quite often-unique selectivity. Hydrogenation, C-H activation, allylic substitution, and numerous other reactions are catalyzed by this metal, which presumably accounts for the dramatic increase in the number of articles that have recently emerged on the topic. P. Andrew Evans, the editor of this much-needed book, has assembled an internationally renowned team to present the first comprehensive coverage of this important area. The book features contributions from leaders in the field of rhodium-catalyzed reactions, and thereby provides a detailed account of the most current developments, including: Rhodium-Catalyzed Asymmetric Hydrogenation (Zhang) Rhodium-Catalyzed Hydroborations and Related Reactions (Brown) Rhodium-Catalyzed Asymmetric Addition of Organometallic Reagents to Electron Deficient Olefins (Hayashi) Recent Advances in Rhodium(I)-Catalyzed Asymmetric Olefin Isomerization and Hydroacylation Reactions (Fu) Stereoselective Rhodium(I)-Catalyzed Hydroformylation and Silylformylation Reactions and Their Application to Organic Synthesis (Leighton) Carbon-Carbon Bond-Forming Reactions Starting from Rh-H or Rh-Si Species (Matsuda) Rhodium(I)-Catalyzed Cycloisomerization and Cyclotrimerization Reactions (Ojima) The Rhodium(I)-Catalyzed Alder-ene Reaction (Brummond) Rhodium-Catalyzed Nucleophilic Ring Cleaving Reactions of Allylic Ethers and Amines (Fagnou) Rhodium(I)-Catalyzed Allylic Substitution Reactions and their Applications to Target Directed Synthesis (Evans) Rhodium(I)-Catalyzed [2+2+1] and [4+1] Carbocyclization Reactions (Jeong) Rhodium(I)-Catalyzed [4+2] and [4+2+2] Carbocyclizations (Robinson) Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions: New Reactions for Organic Synthesis (Wender) Rhodium(II)-Stabilized Carbenoids Containing both Donor and Acceptor Substituents (Davies) Chiral Dirhodium(II)Carboxamidates for Asymmetric Cyclopropanation and Carbon-Hydrogen Insertion Reactions (Doyle) Cyclopentane Construction by Rhodium(II)-Mediated Intramolecular C-H Insertion (Taber) Rhodium(II)-Catalyzed Oxidative Amination (DuBois) Rearrangement Processes of Oxonium and Ammonium Ylides Formed by Rhodium(II)-Catalyzed Carbene-Transfer (West) Rhodium(II)-Catalyzed 1,3-Dipolar Cycloaddition Reactions (Austin) "Modern Rhodium-Catalyzed Organic Reactions" is an essential reference text for researchers at all levels in the general area of organic chemistry. This book provides an invaluable overview of the most significant developments in this important area of research, and will no doubt be an essential text for researchers at academic institutions and professionals at pharmaceutical/agrochemical companies.

Solid catalysts incorporating transition metals are important in industry, providing cost- effective syntheses, ease of separation from products, and control of selectivity. The metal is often expensive and thus often constitutes only about one percent of the catalyst mass, being highly dispersed on a high-area support. Dispersed metals in industrial catalysts are usually highly nonuniform in structure and challenging to characterize, and consequently relationships between structure and catalyst performance are typically less than fully understood. Our approach to the investigation of supported metal catalysts involves the synthesis of uniform catalytic sites that have essentially molecular character. Supported molecular catalysts can be characterized spectroscopically to provide fundamental understanding of the catalyst structure under reactive atmospheres, and thereby determination of structural changes of working catalysts that can be correlated with the catalytic activity and selectivity. The sample characterization techniques used in this work included infrared (IR), extended X-ray absorption fine structure (EXAFS), and X-ray absorption near edge structure (XANES) spectroscopies, as well as gas chromatography (GC) and mass spectrometry (MS) to characterize reaction products. The catalysts were prepared from the organometallic precursor Rh(C2H4)2(C5H7O2) and the supports MgO and zeolite HY. These catalysts initially incorporated site-isolated, mononuclear rhodium complexes on the supports. The complexes on MgO were treated in H2 at elevated temperatures to form the smallest supported rhodium clusters--rhodium dimers. These catalysts are essentially molecular in character and allowed tailoring of the rhodium nuclearity, the ligands bonded to the rhodium, and the rhodium-support interface. The catalysts incorporated mononuclear Rh(C2H4)2 and Rh(CO)2 complexes; dimeric rhodium clusters with ethyl ligands, and dimeric rhodium clusters with CO ligands. These were tested for the hydrogenation of ethylene. Rhodium in various forms is highly active for catalytic hydrogenation of olefins. However, rhodium has been little investigated for diene hydrogenation, because, like other noble metals in the form of supported clusters or particles, it is unselective. We postulated that new catalytic chemistry of rhodium could emerge if the catalytic species were essentially molecular so that they could be tuned by the choice of the rhodium nuclearity and ligands. Thus, we investigated the influence of the following catalyst design variables on the activity and selectivity of supported rhodium for 1,3-butadiene hydrogenation: (a) the metal nuclearity, ranging from one to several; (b) the electron-donor properties of the support (MgO vs. zeolite Y); and (c) other ligands on the rhodium, including reactive hydrocarbons (ethylene or ethyl) and CO. The data show that extremely small MgO-supported rhodium clusters that are partially carbonylated are highly active and selective for the hydrogenation of 1,3-butadiene to give n-butenes. The support, the rhodium nuclearity, and the ligands on rhodium are crucial to the catalyst selectivity, transforming a metal that is typically regarded as unselective for 1,3-butadiene hydrogenation into one that is highly selective even at high conversions. Transition metals in complexes and clusters tend to aggregate to form of more stable, bulk particles under reactive atmospheres, causing catalyst deactivation. We investigated the initial steps of the aggregation of supported metal species that were highly dispersed on MgO and zeolite HY, synthesizing samples that incorporated supported rhodium complexes bonded to ligands with different reactivities (including the support), and then spectroscopically investigated the formation of extremely small rhodium clusters in the presence of H2. The stability of the rhodium complexes and the stoichiometry of the surface-mediated transformations are regulated by the support and the other ligands bonded to the rhodium, being prompted at a lower temperature with zeolite HY than the better electron-donor MgO when the rhodium complexes incorporate ethylene ligands, but occurring more facilely on the MgO than on the zeolite when the ligands are CO. The preparation of highly uniform rhodium dimers is possible. We infer that results such as those presented here may be useful in guiding the design of stable, highly dispersed supported metal catalysts by choice of the support and other ligands on the metal.

Recently, our lab has developed monoanionic tridentate ligand, ToR, showing the corresponding coordination chemistry and catalyst reactivity of magnesium, zirconium, zinc and iridium complexes. This thesis details synthetic chemistry, structural study and catalytic reactivity of the ToR-supported rhodium compounds. Tl[ToR] has been proved to be a superior ligand transfer agent for synthesizing rhodium complexes. The salt metathesis route of Tl[ToM] with [Rh([mu]-Cl)(CO)]2 and [Rh([mu]- Cl)(COE)]2 gives ToMRh(CO)2 (2.2) and ToMRhH([beta]3-C8H13) (3.1) respectively while Tl[ToM] with [Rh([mu]-Cl)(CO)]2 affords ToPRh(CO)2 (2.3). 2.2 reacts with both strong and weak electrophiles, resulting in the oxazoline N-attacked and the metal center-attacked compounds correspondingly. Using one of the metal center-attacked electrophiles, 2.3 was demonstrated to give high diastereoselectivity. Parallel to COE allylic C-H activation complex 3.1, the propene and allylbenzene allylic C-H activation products have also been synthesized. The subsequent functionalization attempts have been examined by treating with Brønsted acids, Lewis acids, electrophiles, nucleophiles, 1,3-dipolar reagents and reagents containing multiple bonds able to be inserted. Various related complexes have been obtained under these conditions, in which one of the azide insertion compounds reductively eliminates to give an allylic functionalization product stoichiometrically. 3.1 reacts with various primary alcohols to give the decarbonylation dihydride complex ToMRh(H)2CO (4.1). 4.1 shows catalytic reactivity for primary alcohol decarbonylation under a photolytic condition. Meanwhile, 2.2 has been found to be more reactive than 4.1 for catalytic alcohol decarbonylation under the same condition. Various complexes and primary alcohols have been investigated as well. The proposed mechanism is based on the stochiometric reactions of the possible metal and organic intermediates. Primary amines, hypothesized to undergo a similar reaction pathway, have been verified to give dehydrogenative coupling product, imines. In the end, the well-developed neutral tridentate Tpm coordinates to the rhodium bis(ethylene) dimer in the presence of TlPF6 to give the cationic complex, [TpmRh(C2H4)2][PF6] (5.1). 5.1 serves as the first example of explicit determination of the solid state hapticity, evidenced by X-ray structure, among all the cationic TpmRM(C2H4)2+ (TpmR = Tpm, Tpm*, M = Rh, Ir) derivatives. The substitution chemistry of this compound has been studied by treating with soft and hard donors. The trimethylphosphine-sbustituted complex activates molecular hydrogen to give the dihydride compound.