In chapter 2, the isolation, characterization, and biological activity of the pyrrole-imidazole alkaloids palau'amine, axinellamines A--D and massadine are reviewed. The proposed biosynthesis of these alkaloids is described and several synthetic approaches toward these alkaloids are discussed.

From the reviews of the First Edition . . . "An excellent text . . . will no doubt provide the benchmark for comparative works for many years."-Journal of the American Chemical Society "A resounding success . . . the definitive current summaries on their respective subjects."-Synthesis Since this important work was first published in 1993, the field of catalytic asymmetric synthesis has grown explosively, spawning effective new methods for obtaining enantiomerically pure compounds on a large scale and stimulating new applications in diverse fields-from medicine to materials science. Catalytic Asymmetric Synthesis, Second Edition addresses these rapid changes through new or substantially revised contributions from highly recognized world leaders in the field. It presents detailed accounts of the most important catalytic asymmetric reactions known today, discusses recent advances, and retains from the previous edition essential and intriguing information on the initial development of certain processes. An excellent working resource for academic researchers and industrial chemists alike, the Second Edition features: * Contributions from Noyori, Sharpless, Kagan, Trost, Overman, Shibasaki, Doyle, Okamoto, Bolm, Carreira, and many other internationally renowned authorities * New chapters on asymmetric carbometallations, asymmetric amplification and autocatalysis, and asymmetric polymerization * Extended coverage of asymmetric carbene reactions, including asymmetric intramolecular carbene insertion to C-H bonds as well as asymmetric dihydroxylation and aminohydroxylation * Extended coverage of asymmetric carbon-carbon bond-forming reactions and applications * An appendix listing all chiral ligands in the book

Giovanni Poli, Guillaume Prestat, Frédéric Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.

This dissertation deals with the development of metal-catalyzed asymmetric allylic alklyations, and their use for the synthesis of alkaloids and other nitrogen-containing biologically active compounds. The synthesis of the drug ( -- )-ranirestat is disclosed, which relies on a Pd-catalyzed asymmetric allylic alkylation (Pd-AAA) as a key step. The development and application of pyrroles and indoles as nucleophiles in the Pd-AAA is described. A Pd-catalyzed decarboxylative asymmetric alkylation approach to constructing vicinal all-carbon quaternary stereocenters is disclosed, and this methodology is used to complete the formal synthesis of several cyclotryptamine alkaloids. Finally, a catalytic asymmetric total synthesis of the alkaloid ( -- )-perophoramidine and efforts towards the alkaloid communesin B are described. Both syntheses employ a molybdenum-catalyzed asymmetric allylic alkylation as a key asymmetric step. ( -- )-Ranirestat is a potent aldose reductase inhibitor currently in phase III clinical testing for its ability to treat diabetic neuropathy. We have developed a concise, catalytic asymmetric total synthesis of ( -- )-ranirestat, which was completed in 8 steps and 14% overall yield starting from inexpensive, commercially available 2-(trichloroacetyl)pyrrole. A palladium-catalyzed asymmetric allylic alkylation (Pd-AAA) of an imidomalonate and an allylic carbonate serve as a key transformation to construct the tetrasubstituted stereocenter in the target with high yield and enantioselectivity. Protiodesilylation followed by oxidative cleavage of the allyl moiety and cyclization are used to access ( -- )-ranirestat. Nitrogen heterocycles are found in a variety of natural products and other biologically active compounds. We have demonstrated that pyrroles and indoles bearing electron-withdrawing groups are competent nucleophiles in the Pd-AAA with vinyl aziridines. The resulting alkylated products were obtained with high levels of regio-, chemo-, and enantioselectivity. Both substituted 1H-pyrroles and 1H-indoles were successfully employed to give exclusively the branched N-alkylated products. The synthetic utility of this asymmetric process was demonstrated through the elaboration of pyrrole products into bromopyrrole alkaloids longamide B, longamide B methyl ester, hanishin, agesamides A and B, and cyclooroidin. Likewise, the synthetic utility of the indole products was demonstrated by elaboration into several patented piperazinones and piperazine medicinal chemistry lead compounds. 1H-Pyrroles have also shown to serve as nucleophiles with meso electrophiles in the Pd-AAA. The products from this transformation were obtained as a single regio- and diastereomer in high yield and % ee. To demonstrate synthetic utility, a pyrrole-substituted nucleoside analogue was synthesized employing this methodology as the asymmetric step. Quaternary all-carbon stereocenters are present in many natural products and biologically active compounds. The presence of this structural element greatly complicates the asymmetric assembly of molecules due to steric congestion. The asymmetric assembly is complicated further when a second vicinal, quaternary center is present in a molecular target. We have discovered that a two-fold Pd-DAAA of an oxindole-derived dienol carbonate can be used to construct two vicinal all carbon quaternary stereocenters in a diastereo- and enantioselective fashion. To demonstrate the synthetic utility of this process, the product of this transformation was used to complete the formal syntheses of the cyclotryptamine alkaloids ( -- )-chimonanthine, (+)-calycanthine ( -- )-folicanthine, and ditryptophenaline. Mechanistic investigations have suggested that the two-fold Pd-catalyzed transformation proceeds through an unusual matched and mismatched allylation to deliver the desired product. Perophoramidine was isolated from the ascidian organism Perophora namei and displays cytotoxicity toward the HCT116 colon carcinoma cell line with an IC50 of 60 æM. The complex polycyclic cage-like core of this alkaloid makes it a challenging and interesting target for total synthesis. A catalytic asymmetric total synthesis of ( -- )-perophoramidine was developed employing a molybdenum-catalyzed asymmetric allylic alkylation between an allylic phosphate and an alkyl oxindole as an asymmetric step. This key transformation provides a chiral oxindole product in high yield and with high levels of regio-, diastereo-, and enantioselectivity. The chiral oxindole product, which contains the key quaternary stereocenter present in perophoramidine, was further elaborated to a pentacyclic imino ether using a reductive cyclization, oxidative cleavage and lactamization as key transformations. The imino ether was alkylated with allyl iodide to construct the second vicinal quaternary stereocenter providing an allyl imino ether as a single regio- and diastereomer. The allyl imino ether was converted to an aldehyde via ozonolysis, which was subjected to a reductive amination and cyclization sequence to complete ( -- )-perophoramidine.

This thesis addresses two fundamental areas in contemporary organic chemistry: synthesis of natural products and catalytic asymmetric synthesis. Firstly, a new methodology, developed by our research group, which allows the asymmetric synthesis of lactones, a structural unit ubiquitous in natural products, was utilised in the synthesis of a number of natural product analogues that showed significant biological activity. Secondly, the development of a catalytic asymmetric synthesis of a key structural motif present in a number of natural products and pharmaceuticals was accomplished. During the course of this work we discovered dual stereo control, which is significant because it allows the configuration of a new stereo centre to be controlled by a simple change of proton source.

Written by world-renowned and best-selling experts, Nobel Laureate E. J. Corey and Laszlo Kurti, Enantioselective Chemical Synthesis offers an authoritative and comprehensive overview of the field's progress; the processes and tools for key formations; future development for complex, stereocontrolled (enantiomeric or diastereoisomeric) molecules; and valuable examples of multi-step syntheses. Utilizing a color-coded scheme to illustrate chemical transformations, Enantioselective Chemical Synthesis provides clear explanation and guidance through vital asymmetrical syntheses and insight into the next steps for the field. Researchers, professionals, and academics will benefit from this valuable, thorough, and unique resource. - In Part I, the authors present clearly, comprehensively and concisely the most useful enantioselective processes available to synthetic chemists. - Part II provides an extensive discussion of the most logical ways to apply these new enantioselective methods to the planning of syntheses of stereochemically complex molecules. This hitherto neglected area is essential for the advancement of enantioselective synthesis to a more rational and powerful level. - Part III describes in detail many reaction sequences which have been used successfully for the construction of a wide variety of complex target molecules - Clearly explains stereochemical synthesis in theory and practice - Provides a handy tool box for scientists wishing to understand and apply chiral chemical synthesis - Describes almost 50 real life examples of asymmetric synthesis in practice and examines how the chiral centers were introduced at key synthetic stages

The chapters in this volume have been written by some of the foremost practictioners in the field and should be of interest to both mechanistic and synthetic chemists.

Asymmetric Synthesis, Volume 3: Stereodifferentiating Addition Reactions, Part B presents intensive investigations in leading academic and industrial laboratories on stereodifferentiating addition reactions. This book is divided into eight chapters and begins with a comprehensive review of the formation of chiral metal enolates and their stereoselective alkylation reactions. These topics are followed by discussions on chiral Aldol addition reactions and the many variations of asymmetric synthesis that may be carried out using chiral oxazolines. A chapter describes the alkylation of chiral hydrazones, a process that yields chiral-substituted aldehydes and ketones. Other chapters explore a variety of cyclization processes that form carbon-carbon and carbon-heteroatom bonds. The last chapters deal with the asymmetric cycloadditions and sigma-tropic rearrangements. Synthetic chemists and researchers will find this book invaluable.

A veritable "Who's who" of asymmetric synthesis introduces the reader to the leaders in the field with a four-page concentrate of their area of research along with a short biography. The book is organized into five chapters, each with an introductory preface. Starting from the key concepts of asymmetric synthesis diastereoselective methods, asymmetric catalysis) the Focus then shifts to its application to the synthesis natural products and industrial processes. Graduate students, academic and industrial researchers will find this book a rich source of inspiration for their own work as well as an indispensable tool for the preparation of seminars and exams. A must for everyone in the field.