Studies Of Rhodium Catalyzed 5 2 Cycloadditions And Their Applications In Organic Synthesis

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.

Transition metal-catalyzed cycloaddition reaction is one of the most efficient ways to access ring systems and remains to be one of the most active areas in organic chemistry. The discovery of 3-acyloxy-1,4-enyne (ACE) and 3-hydroxy-1,4-enyne (HYE) as the five-carbon components has led to the development of various Rh-catalyzed [5+1] and [5+2] cycloadditions in our group. These novel methods offered efficient access to highly substituted six- and seven-membered carbocycles. I will present our progresses on the development, application and mechanistic studies of the following four [5+1] and [5+2] cycloadditions. 1) Using ACE bearing an electron-rich ester as the five-carbon component, a [5+1] cycloaddition was realized under mild conditions for the preparation of highly substituted phenols. 2) Based on our previous success on Rh-catalyzed intermolecular [5+2] cycloaddition of ACE and alkynes, a library of highly substituted tropones was successfully prepared by modifying the cycloheptatriene products derived from the [5+2] cycloaddition. 3) The scope of the Rh-catalyzed intramolecular [5+2] cycloaddition of ACE with alkenes was expanded and the Rh-catalyzed intramolecular [5+2] cycloaddition of ACE with allenes was developed for the synthesis of highly functionalized bicyclic 5-7 fused ring systems with multiple stereogenic centers. 4) Using HYE as the 5-carbon component, a [5+1] carbonylative benzannulation reaction was previously developed in our group for the synthesis of tricyclic carbazoles. The scope of this tandem reaction is now expanded to the synthesis of tetra- and even pentacyclic ring systems including furocarbazoles, thiophenocarbazole, pyrrolocarbazole, and indolocarbazole. Metal carbene intermediates are involved in most of these cycloadditions. The strategy of using propargylic esters and propargylic alcohols as the Rh(I) carbene precursor should have broad implications in transition metal catalysis and metal carbene chemistry.

Transition metal-catalyzed cyloaddition and cycloisomerization reactions occupy a central position within the realm of organic synthesis. Research described in this thesis focuses on using propargylic esters and alcohols as building blocks for rhodium(I)-catalyzed cycloadditions and cycloisomerizations. The discovery and application of combining the [pi]-acidity and redox/insertion reactivity of rhodium(I) complexes, led to the development of many new reactions. By taking advantage of Rh-catalyzed 1,3-acyloxy migration of propargylic esters, I developed two tandem reactions. One is Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes (ACEs) for the synthesis of highly substituted cyclopentenones, and the other is ring expansion of cyclopropanes or cyclobutanes for the preparation of highly functionalized seven-membered or eight-membered carbocycles. By taking advantage of Rh-catalyzed 1,2-acyloxy migration of propargylic esters adjacent to heterocycles, I developed a novel and practical method for the preparation of a series of heterocycles including indoles, benzofurans, carbazoles and benzothiophenes from substituted pyrroles, furans, indoles and thiophenes. Inspired by the first Rh-catalyzed intra- and intermolecular [5+2] cycloadditions of 3-acyloxy-1,4-enynes (ACEs) with alkynes, I developed a new five-carbon building block, an inverted ACE, for [5+2] cycloadditions by switching the position of the alkene and alkyne groups in ACE. By replacing the acyloxy group in ACE with OH leaving group and aniline nucleophile, a completely new type of 5-carbon building block (HYE) was designed for cycloadditions. The tandem indole annulation and [5+1] cycloaddition was realized for the synthesis of various highly substituted carbazoles. Natural products glycosinine and mahanimbine were prepared. Furthermore, indolyl Rh(I)-carbene could be generated from 3-hydroxy-1,4-enyne (HYE) through a dehydration process. With different N-protecting group, I prepared dimeric indoles, cyclopropyl indoles, vinyl indoles and other interesting indole derivatives.

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.

Advanced tools for developing new functional materials and applications in chemical research, pharmaceuticals, and materials science Cycloadditions are among the most useful tools for organic chemists, enabling them to build carbocyclic and heterocyclic structures. These structures can then be used to develop a broad range of functional materials, including pharmaceuticals, agrochemicals, dyes, and optics. With contributions from an international team of leading experts and pioneers in cycloaddition chemistry, this book brings together and reviews recent advances, trends, and emerging research in the field. Methods and Applications of Cycloaddition Reactions in Organic Syntheses focuses on two component cycloadditions, with chapters covering such topics as: N1 unit transfer reaction to C–C double bonds [3+2] Cycloaddition of α, β-unsaturated metal-carbene complexes Formal [3+3] cycloaddition approach to natural product synthesis Development of new methods for the construction of heterocycles based on cycloaddition reaction of 1,3-dipoles Cycloreversion approach for preparation of large π-conjugated compounds Transition metal-catalyzed or mediated [5+1] cycloadditions Readers will learn methods for seamlessly executing important reactions such as Diels-Alder and stereoselective dipolar reactions in order to fabricate heterocyclic compounds, natural products, and functional molecules. The book not only features cutting-edge topics, but also important background information, such as the contributors’ process for developing new methodologies, to help novices become fully adept in the field. References at the end of each chapter lead to original research papers and reviews for facilitating further investigation of individual topics. Covering the state of the science and technology, Methods and Applications of Cycloaddition Reactions in Organic Syntheses enables synthetic organic chemists to advance their research and develop new functional materials and applications in chemical research, pharmaceuticals, and materials science.

This is the accompanying workbook to the textbook "Organic Chemistry - Theory, Reactivity and Mechanisms in Modern Synthesis" by P. Vogel and K. Houk.