Progress Towards Total Synthesis of Lyconadin A 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 Progress Towards Total Synthesis of Lyconadin A PDF full book. Access full book title Progress Towards Total Synthesis of Lyconadin A by Yu Zhang. Download full books in PDF and EPUB format.
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: 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: Douglas C. Beshore
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Sarah Etheredge Danishefsky
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages :
Get Book Here
Book Description
Author: Miguel A. Sierra
Publisher: John Wiley & Sons
ISBN: 352765464X
Category : Science
Languages : en
Pages : 297
Get Book Here
Book Description
Success comes in many forms and in synthesis it can be a failure that results in their ultimate successful solutions. This long-awaited sequel to "Dead Ends and Detours" retains the proven concept while featuring over 20 new case studies of failed strategies and their (successful) solutions in natural product total synthesis. Additionally, computational models are used to discuss the problem in much more detail and to provide readers with additional information not found in the primary literature. The topics range from classic synthetic reactions (e.g. Diels Alder reaction), metal-mediated coupling reactions, metathesis, and asymmetric catalysis to the importance of protecting and activating groups. This book will benefit not only graduate students in organic chemistry but also advanced researchers as they gain knowledge derived from the step-by-step analysis of mistakes made in the past and, thus be able to improve their own chemical reaction planning. With its coverage of the most commonly applied reaction types, the book perfectly complements its predecessor, which focuses on general aspects, such as reactivity and selectivity.
Author: Gloria Shen Lee
Publisher:
ISBN:
Category :
Languages : en
Pages : 142
Get Book Here
Book Description
In Chapter 1, potential strategies toward the synthesis of rugulosone were investigated. Although initial efforts towards forming the bicyclo[3.3.1]nonane core via a Michael addition - Dieckmann condensation reaction sequence did not prove useful for our investigations, the synthesis of the core was accomplished via a highly efficient tetraalkylation of commercially available starting materials. Using our developed methodology, we were able to isomerize unactivated alkenes to form the C2 symmetric core necessary for the natural product. Studies toward the addition of the northern side chain were conducted, and proved to be promising. Synthesis of a protected southern side chain was accomplished, and may be used in the future to couple with the functionalized core to facilitate a highly divergent synthesis of the natural product. For our work towards the synthesis of the core of rugulosone, we developed a methodology to isomerize exo-methylene groups to their corresponding tri-substituted internal alkenes. The exo-methylene groups of 2,6-disubstituted bicyclo[3.3.1]nonan-9-ones were readily isomerized over a palladium catalyst under an atmosphere of hydrogen to form predominantly the isomer with C2 symmetry with very little formation of the analogous product with CS symmetry. A hydrogen source was essential to effect the rearrangement. The third and last chapter outlines formation of highly substituted adamantanones. Adamantane-based small molecules are useful in the treatment of a variety of conditions, ranging from neurodegenerative disorders such as Parkinson's and Alzheimer's disease, to viral infections such as HIV. We thus desired to efficiently construct substituted adamantanones, potential precursors to the corresponding adamantanes. Trifluoromethanesulfonic acid facilitated formation of the adamantanone core from 1,5-dialkyl-3,7-dimethylenebicyclo[3.3.1]nonan-2-one, which was easily obtained in one step from commercially available starting materials. The resulting adamantyl cation was trapped with a variety of nucleophiles to form tetrasubstituted adamantanones. Aromatic and heteroaromatic nucleophiles have proven to be successful, and oxygen and nitrogen nucleophiles provide access to a wide variety of functionality at the newly formed tertiary position.
Author: Bohan Jin
Publisher:
ISBN:
Category :
Languages : en
Pages : 604
Get Book Here
Book Description
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:
Publisher:
ISBN:
Category :
Languages : en
Pages : 265
Get Book Here
Book Description
Author: Gordon Gribble
Publisher: Elsevier
ISBN: 0080914950
Category : Science
Languages : en
Pages : 497
Get Book Here
Book Description
This is the 20th annual volume of Progress in Heterocyclic Chemistry, which covers the literature published during 2007. As with previous volumes in the series, Volume 20 will enable the reader to keep abreast of developments in heterocyclic chemistry in an effortless way.* A critical review of the heterocyclic literature published during 2007 * Presents specialized reviews * Chapters all written by leading researchers in their field
Author: Nathan Miller
Publisher:
ISBN:
Category :
Languages : en
Pages : 240
Get Book Here
Book Description
