Total Synthesis of (+)-Lyconadin A and (-)-Lyconadin B 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 Total Synthesis of (+)-Lyconadin A and (-)-Lyconadin B PDF full book. Access full book title Total Synthesis of (+)-Lyconadin A and (-)-Lyconadin B by Douglas C. Beshore. Download full books in PDF and EPUB format.
Author: Douglas C. Beshore
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Douglas C. Beshore
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Yu Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 173
Get Book Here
Book Description
Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium complanatum with antitumor properties. We have developed a novel 7-exo/6-exo acyl radical cascade cyclization as a method of making the bicyclo[5.4.0]undecane ring system of lyconadin A. The model products are trans-fused ring systems, while a cis-fused ring system is needed in lyconadin A. We have discovered a method to convert the trans-fused model cascade cyclization product into the desired cis isomer. Based on Donohoe's pyridone synthesis, we developed a method for the construction of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones, the former of which is a subunit of lyconadin A. An intramolecular Reformatsky reaction is a key step in this process. We have proceeded with our total synthesis, in which we generated an epoxide by Shi asymmetric epoxidation and regioselectively opened epoxide rings. We have prepared carboxylic acid 197.
Author: Scott P. West
Publisher:
ISBN:
Category :
Languages : en
Pages : 490
Get Book Here
Book Description
An overview of the Lycopodium alkaloids is presented covering their isolation, structural classification and biosynthesis. The isolation, biological activity and biosynthesis of the miscellaneous group of the Lycopodium alkaloids are discussed in detail. Synthetic studies on the miscellaneous Lycopodium alkaloids are summarized and an overview of a previous total synthesis of (+)-lyconadin A and an approach to lyconadin A is presented. The development of a unified strategy to access several miscellaneous Lycopodium alkaloids has been achieved. Utilizing this approach, the racemic and enantioselective syntheses of lyconadin A were achieved in 17 steps. Key strategic bond formations in the synthesis include olefin cross-metathesis, intramolecular Heck reaction, Curtius rearrangement, and intramolecular reductive amination. The lyconadin pentacycle was assembled by an unprecedented oxidative C-N bond-forming reaction from a dianion intermediate. The enantioselective route utilizes a Corey-Bakshi-Shibata reduction and a diastereoselective hydrogenation to set three key stereocenters. An overview of oxidative bond-forming reactions from dianion intermediates is presented. The mechanism of the oxidative C-N bond formation was examined. NMR studies and DFT calculations were conducted to investigate the structure of the dianion intermediate. Several oxidants were found to promote C-N bond formation by oxidation of the dianion intermediate. The reactivity studies revealed that the C-N bond formation may proceed by polar or SET mechanisms and that the mechanistic pathway is dependent on the type of oxidant utilized.
Author: Xiayun Cheng
Publisher:
ISBN:
Category :
Languages : en
Pages : 680
Get Book Here
Book Description
A total synthesis of the bridge-fused Aspidosperma indole alkaloid (±) has been accomplished in seven steps starting from the commercially available tryptamine. The bridge-containing scaffold of (±)-subincanadine F was efficiently assembled by a low valent titanium mediated intramolucular nucleophilic acyl substiutution (INAS) reaction. The synthetic utility of titanium-medicated INAS reagents for heterocyclic compounds was further demonstrated.
Author: Sarah Elizabeth House
Publisher:
ISBN:
Category :
Languages : en
Pages : 370
Get Book Here
Book Description
A unified approach to the total synthesis of Lycopodium alkaloids belonging to the miscellaneous class has been developed, wherein a single tetracyclic amine is employed as a common intermediate in synthetic studies toward several alkaloids. An overview of Lycopodium alkaloids is presented, including their structural classification, isolation and biological activity. The biosynthesis of alkaloids in the miscellaneous group is discussed in depth. A summary of previous synthetic work focusing on miscellaneous Lycopodium alkaloids is presented, including total syntheses of luciduline, lyconadins A and B and nankakurines A and B.A model study of spirolucidine is discussed. A biomimetic route to access spirolucidine and nankakurine B has been investigated. In this study, a tetracyclic amine that is a key intermedite in the total synthesis of lyconadin A previously developed in our laboratory is elaborated into a tertiary alcohol that mimics the proposed biosynthetic precursor of nankakurine B.A biomimetic ring-contractive [alpha]-hydroxyimine rearrangement to generate nankakurine B has been extensively investigated and found to be disfavored. The conversion of a tricyclic ketone (first synthesized en route to lyconadin A) to the tetracyclic core of serratezomine D has been investigated. The core of this molecule was inaccessible via methods employed in the studies toward lyconadin A. The total synthesis of 1'-epi-dihydrolycolucine from the key common tetracyclic amine intermediate has been achieved. Studies toward the synthesis of serratezomine E served as a platform to develop this method and to determine the stereochemical outcome of this reaction.
Author: Koudi Zhu
Publisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 74
Get Book Here
Book Description
Lyconadin A is an alkaloid possessing a unique structure and antitumor activity. The total synthesis of Lyconadin A was proposed via an acyl radical cascade reaction. To investigate the possibility and stereoselectivity of the cascade cyclization, phenyl selenoester 16 was chosen as a model substrate to study the 7-exo-5-exo radical cyclization. A synthetic route to phenyl selenoester 16 was developed. The 7-exo-5-exo radical cyclization was found to occur with a high yield and excellent stereoselectivty. Attempts were also tried to synthesize another radical precursor 14 albeit with less success. A synthetic pathway to the synthesis of 14 as well as its potential use in the context of the synthesis of Lyconadin A was proposed.
Author: Krishna C. Majumdar
Publisher: John Wiley & Sons
ISBN: 3527634894
Category : Science
Languages : en
Pages : 648
Get Book Here
Book Description
Filling a gap on the market, this handbook and ready reference is unique in its discussion of the usefulness of various heterocyclic systems in the synthesis of natural products. Clearly structured for easy access to the information, each chapter is devoted to a certain class of heterocycle, providing a tabular presentation of the natural products to be covered containing the particular heterocyclic ring system along with their biological profile, occurrence and most important physical properties, backed by the appropriate references. In addition, the application of the heterocyclic system to the synthesis of natural products ic covered in detail. Of great interest to organic, natural products, medicinal and biochemists, as well as those working in the pharmaceutical and agrochemical industry.
Author: Michael Harmata
Publisher: Academic Press
ISBN: 0123865409
Category : Chemistry, Organic
Languages : en
Pages : 456
Get Book Here
Book Description
A classic in the area of organic synthesis, Strategies and Tactics in Organic Synthesis provides a forum for investigators to discuss their approach to the science and art of organic synthesis. Rather than a simple presentation of data or a second-hand analysis, this book vividly demonstrates through first hand accounts how synthesis is really done and how by discovering new reactions, creating new designs and building molecules with atom and step economies, the advancement of the science of organic synthesis is providing solutions through function to create a better world. Presents state-of-the-art developments in organic synthesisProvides insight and offers new perspective to problem-solvingWritten by leading experts in the field.
Author:
Publisher: Academic Press
ISBN: 0124078524
Category : Science
Languages : en
Pages : 311
Get Book Here
Book Description
This series is world-renowned as the leading compilation of current reviews of this vast field. Internationally acclaimed for more than 40 years, The Alkaloids, founded by the late Professor R.H.F. Manske, continues to provide outstanding coverage of this rapidly expanding field. Each volume provides, through its distinguished authors, up-to-date and detailed coverage of particular classes or sources of alkaloids. - Up-to-date reviews on a large and very important group of natural products from both a chemical and biological perspective - Comprehensive, dynamic reviews written by leading authors in the respective fields - Broad coverage on the biological aspects
Author: Lisa-Catherine Rosenbaum
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
