Stereoselective Formation of All Carbon Quaternary Centers PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Stereoselective Formation of All Carbon Quaternary Centers PDF full book. Access full book title Stereoselective Formation of All Carbon Quaternary Centers by Erica Anne Tiong. Download full books in PDF and EPUB format.
Author: Erica Anne Tiong
Publisher:
ISBN: 9780494787113
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Erica Anne Tiong
Publisher:
ISBN: 9780494787113
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Corey Michael Reeves
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Notwithstanding advances in modern chemical methods, the selective installation of sterically encumbered carbon stereocenters, in particular all-carbon quaternary centers, remains an unsolved problem in organic chemistry. The prevalence of all-carbon quaternary centers in biologically active natural products and pharmaceutical compounds provides a strong impetus to address current limitations in the state of the art of their generation. This thesis presents four related projects, all of which share in the goal of constructing highly-congested carbon centers in a stereoselective manner, and in the use of transition-metal catalyzed alkylation as a means to address that goal. The first research described is an extension of allylic alkylation methodology previously developed in the Stoltz group to small, strained rings. This research constitutes the first transition metal-catalyzed enantioselective alpha-alkylation of cyclobutanones. Under Pd-catalysis, this chemistry affords all - carbon alpha-quaternary cyclobutanones in good to excellent yields and enantioselectivities. Next is described our development of a (trimethylsilyl)ethyl beta-ketoester class of enolate precursors, and their application in palladium-catalyzed asymmetric allylic alkylation to yield a variety of alpha-quaternary ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to allyl beta-ketoester substrates; highly functionalized alpha-quaternary ketones generated by the union of our fluoride-triggered beta-ketoesters and sensitive allylic alkylation coupling partners serve to demonstrate the utility of this method for complex fragment coupling. Lastly, our development of an Ir-catalyzed asymmetric allylic alkylation of cyclic beta-ketoesters to afford highly congested, vicinal stereocenters comprised of tertiary and all-carbon quaternary centers with outstanding regio-, diastereo-, and enantiocontrol is detailed. Implementation of a subsequent Pd-catalyzed alkylation affords dialkylated products with pinpoint stereochemical control of both chiral centers. The chemistry is then extended to include acyclic bega-ketoesters and similar levels of selective and functional group tolerance are observed. Critical to the successful development of this method was the employment of iridium catalysis in concert with N-aryl-phosphoramidite ligands.
Author: Biana Island
Publisher:
ISBN:
Category :
Languages : en
Pages : 69
Get Book Here
Book Description
Author: Jiajie Feng
Publisher:
ISBN:
Category :
Languages : en
Pages : 688
Get Book Here
Book Description
All-carbon quaternary stereocenters are ubiquitous in bioactive natural products as well as pharmaceutical molecules. However, stereoselective access of these structural motifs is still a challenge in synthetic chemistry. Therefore, a general method that can construct quaternary carbon centers diastereo- and enantioselectively is in high demand. Redox-triggered stereoselective C-C bond forming reactions via metal-catalyzed transfer hydrogenation are able to avoid usage of sensitive preformed organometallic reagents and formation of stoichiometric metal waste. Efforts have been focused on the development of efficient methods for diastereo- and enantioselective generation of quaternary centers via iridium-catalyzed tert-(hydroxy)prenylation of alcohols and aldehydes. Applying this methodology to modular syntheses of terpenoid natural products oridamycin A, triptoquinones B and C, isoiresin and andrographolide in the most concise routes is described.
Author: Jens Christoffers
Publisher: John Wiley & Sons
ISBN: 3527606971
Category : Science
Languages : en
Pages : 359
Get Book Here
Book Description
Filling the gap in the literature, this book presents everything there is to know about this topic. By comprehensively covering the quaternary stereocenters found in a range of important and useful molecules in pharmaceutical and medicinal applications, as well as in thousands of natural products, the book provides the know-how chemists need to synthesize challenging molecules with numerous applications. A must for organic chemists in academia, the pharmaceutical industry and medicine. From the Contents: Important Natural Products Important Pharmaceuticals and Intermediates Aldol Reactions Michael Reactions and Conjugate Additions Cycloaddition Reactions Rearrangement Reactions Alkylation of Ketones and Imines Asymmetric Allylic Alkylation Asymmetric Cross Coupling and Heck Reactions Phase Transfer Catalysis Enzymatic Methods Radical Reactions
Author:
Publisher: Newnes
ISBN: 0080951686
Category : Science
Languages : en
Pages : 5635
Get Book Here
Book Description
Although many books exist on the subject of chiral chemistry, they only briefly cover chiral synthesis and analysis as a minor part of a larger work, to date there are none that pull together the background information and latest advances in one comprehensive reference work. Comprehensive Chirality provides a complete overview of the field, and includes chiral research relevant to synthesis, analytic chemistry, catalysis, and pharmaceuticals. The individual chapters in each of the 9 volumes provide an in depth review and collection of references on definition, technology, applications and a guide/links to the related literature. Whether in an Academic or Corporate setting, these chapters will form an invaluable resource for advanced students/researchers new to an area and those who need further background or answers to a particular problem, particularly in the development of drugs. Chirality research today is a central theme in chemistry and biology and is growing in importance across a number of disciplinary boundaries. These studies do not always share a unique identifying factor or subject themselves to clear and concise definitions. This work unites the different areas of research and allows anyone working or researching in chiral chemistry to navigate through the most essential concepts with ease, saving them time and vastly improving their understanding. The field of chirality counts several journals that are directly and indirectly concerned with the field. There is no reference work that encompasses the entire field and unites the different areas of research through deep foundational reviews. Comprehensive Chirality fills this vacuum, and can be considered the definitive work. It will help users apply context to the diverse journal literature offering and aid them in identifying areas for further research and/or for solving problems. Chief Editors, Hisashi Yamamoto (University of Chicago) and Erick Carreira (ETH Zürich) have assembled an impressive, world-class team of Volume Editors and Contributing Authors. Each chapter has been painstakingly reviewed and checked for consistent high quality. The result is an authoritative overview which ties the literature together and provides the user with a reliable background information and citation resource.
Author: Kengadarane Anebouselvy
Publisher: Royal Society of Chemistry
ISBN: 1782620907
Category : Science
Languages : en
Pages : 220
Get Book Here
Book Description
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.
Author: Jinzhen Lin
Publisher:
ISBN:
Category :
Languages : en
Pages : 534
Get Book Here
Book Description
Author: Liat Frid
Publisher:
ISBN:
Category :
Languages : en
Pages : 89
Get Book Here
Book Description
Author: Ramon Rios Torres
Publisher: John Wiley & Sons
ISBN: 1118604709
Category : Science
Languages : en
Pages : 581
Get Book Here
Book Description
Sets forth an important group of environmentally friendly organic reactions With contributions from leading international experts in organic synthesis, this book presents all the most important methodologies for stereoselective organocatalysis, fully examining both the activation mode as well as the type of bond formed. Clear explanations guide researchers through all the most important methods used to form key chemical bonds, including carbon-carbon (C–C), carbon-nitrogen (C–N), and carbon-halogen (C–X) bonds. Moreover, readers will discover how the use of non-metallic catalysts facilitates a broad range of important reactions that are environmentally friendly and fully meet the standards of green chemistry. Stereoselective Organocatalysis begins with an historical overview and a review of activation modes in asymmetric organocatalysis. The next group of chapters is organized by bond type, making it easy to find bonds according to their applications. The first of these chapters takes a detailed look at the many routes to C–C bond formation. Next, the book covers: Organocatalytic C–N bond formation C–O bond formation C–X bond formation C–S, C–Se, and C–B bond formation Enantioselective organocatalytic reductions Cascade reactions forming both C–C bonds and C–heteroatom bonds The final chapter is devoted to the use of organocatalysis for the synthesis of natural products. All the chapters in the book are extensively referenced, serving as a gateway to the growing body of original research reports and reviews in the field. Based on the most recent findings and practices in organic synthesis, Stereoselective Organocatalysis equips synthetic chemists with a group of organocatalytic reactions that will help them design green reactions and overcome many challenges in organic synthesis.
