A four component reaction involving the coupling of functionalized aldehydes, amines, acid chlorides, and [pi]- and organometallic nucleophiles has been developed to prepare multifunctional substrates that may be employed in subsequent ring-forming reactions to generate diverse arrays of functionalized heterocyclic scaffolds. Allyl metals, Grignard reagents, silyl ketene acetals, silyl enol ethers, and silyloxy furans have been utilized as the nucleophile in the four component reaction (4CR). The 4CR has been sequenced with intramolecular Heck reactions, Diels-Alder and (3+2) cycloadditions, ring closing metathesis (RCM), and Dieckmann condensations to provide a number of diverse heterocyclic structures. The practical utility of this approach to diversity-oriented synthesis (DOS) was further exemplified by its application to the first total synthesis of the isopavine alkaloid roelactamine, which was completed in only four steps from commercially available materials. The application of this methodology towards the synthesis of the Aspidosperma alkaloids rosicine and pseudotabersonine is also presented. To this end, an imine pentadienylation/double RCM strategy has been adopted to rapidly access the pentacyclic core of the aspidospermine alkaloids. This sequence involved the use of a pentadienyl aluminum reagent, which was found to react with aryl imines to give branched products in good yields.

Synthesis of Six- and Seven-Membered Heterocycles: The Role of DMF and its Synthesis compares different synthetic approaches using DMF, including the advantages and disadvantages of those reactions, green methods, and the sustainability of reported synthetic methodologies, especially the microwave methods. The book presents several methodologies for the synthesis of six- and seven-membered heterocyclic compounds using dimethylformamide. Users will find the most up-to-date information in this fast-moving field which can be particularly challenging. With DMF drawing the attention of synthetic organic chemists, this book will help readers understand further developments in the uses of dimethylformamide beyond just its use as a polar solvent. As it can be expected that the use of dimethylformamide as a precursor will continue to grow in organic synthesis with new applications in sustainable and green chemistry, this book provides an ideal primer on the topics covered. Compares different methods, reagents, reaction conditions, advantages and disadvantages Discusses and compares different methodologies with green techniques Includes reaction schemes, reaction mechanisms and the structure of reactive intermediates

Synthesis of Five-Membered Heterocycles: Role of DMF as Solvent, Reagent, Catalyst, and Stabilizer helps readers quickly assess possible synthetic approaches. The book's audience, researchers, academic professionals and synthetic chemists both in industry and academia will find detailed information about the synthesis of five-membered heterocyclic compounds using dimethylformamide. Over the years, heterocyclic compounds, especially five-membered, have drawn more attention of pharmaceutical community because of their therapeutic value. The formation of heterocyclic compounds has turned out to be the keystone of synthetic organic chemistry. Dimethylformamide has played an important role in organic synthesis for a long time, and it is frequently utilized as a common solvent for chemical reactions and broadly used in industry as a reagent. It is a unique chemical and can play three other roles in organic chemistry, i.e., as stabilizer, reagent and catalyst. Due to its structure, DMF can participate in several reactions as a versatile building block for several units. Includes comprehensive descriptions of heterocycle synthesis Highlights many methods for the synthesis of five-membered heterocyclic compounds using dimethylformamide Helps readers quickly assess possible synthetic approaches

Recent Applications of Selected Name Reactions in the Total Synthesis of Alkaloids includes comprehensive coverage of name reactions in the synthesis of alkaloids. This book highlights the synthesis of various alkaloids using special name reactions including the Diels-Alder, Friedel-Crafts, Heck, Mannich, Pauson-Khand, Pictet-Spengler, Sonogashira and Suzuki reactions. In this book, some selected name reactions in the total synthesis of alkaloids are covered, as they can be used as the key step/steps in the synthesis of different alkaloids exhibiting various biological activities. All chapters include an introduction, history and mechanism of the name reaction, and present the origin of the natural product and its known biological activities. The pathway to total synthesis is visually illustrated, and the focus is on the step in which a name reaction is applied. Chemists working in the area of synthetic organic chemistry will find this reference useful, as well as those working to develop novel methodologies for the synthesis of natural products in both academia and industry. This book is also beneficial to biologists, pharmacists and botanists. Includes an introduction of alkaloids, their origins and biological properties Features the applications of special name reactions as the key step in the total synthesis of featured alkaloids Covers the pathway for the synthesis of alkaloids from commercially available or easily accessible starting materials by using at least one name reaction to achieve the desired target products

Several novel multicomponent assembly processes have been developed for the preparation of a diverse array of complex heterocyclic systems from relatively simple starting materials. These studies resulted in the discovery of a new quinazolone forming reaction, which was applied to the one-step synthesis of the quinazolinocarboline alkaloid rutaecarpine. Biological screening of these complex heterocycles culminated in the identification of a potent sigma-2 receptor ligand. A novel N-acyliminium ion mediated cascade reaction was employed for the concise synthesis of (±)-actinophyllic acid. The completion of the synthesis relied on the development of a reaction sequence that avoided a potentially detrimental fragmentation process. Furthermore, several anti-cancer compounds were identified through a diverted total synthesis approach.

In the last decade a new era in asymmetric catalysis has been realised by the discovery of L-proline induced chiral enamines from carbonyls. Inspired by this, researchers have developed many other primary catalytic species in situ, more recently secondary catalytic species such as aminals have been identified for use in asymmetric synthesis. High-yielding asymmetric synthesis of bioactive and natural products through mild catalysis is an efficient approach in reaction engineering. In the early days, synthetic chemists mainly focused on the synthesis of complex molecules, with less attention on the reaction efficiency and eco-friendly conditions. Recent investigations have been directed towards the development of atom economy, eco-friendly and enantioselective synthesis for more targeted and efficient synthesis. Building on the momentum of this rapidly expanding research area, Dienamine catalysis for organic synthesis will provide a comprehensive introduction, from the preformed species, in situ generation and onto their applications in the synthesis of bioactive molecules and natural products.

This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.