Allene Cycloisomerization, Epoxidation, and Applications in Total Synthesis 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 Allene Cycloisomerization, Epoxidation, and Applications in Total Synthesis PDF full book. Access full book title Allene Cycloisomerization, Epoxidation, and Applications in Total Synthesis by Joseph Ryan Cusick. Download full books in PDF and EPUB format.
Author: Joseph Ryan Cusick
Publisher:
ISBN:
Category : Allene
Languages : en
Pages : 398
Get Book Here
Book Description
Disclosed are studies on the structure and reactivity of allenes and spirodiepoxides (SDEs) and their application to synthesis. A novel ruthenium promoted cycloisomerization of [gamma]-enallenes to cyclopentenes was discovered. The effects of solvent, oxidant, and substrate structure on the stereoselectivity of SDE formation from 1,3-disubstituted and trisubstituted allenes were evaluated. A computational model was advanced for the rationalization of observed selectivity in such formations. The known acid instability of SDEs was exploited to effect a designed rearrangement of [beta]-silyl SDE to an [alpha]-hydroxy enone. Silyl-substituted SDEs were utilized to give carbinol substituted heterocycles with excellent ee, [alpha]-hydroxy enones, as well as [alpha], [beta]-dihydroxy olefins. A silyl-SDE approach was used to accomplish a short and efficient total synthesis of the natural product, epi-citreodiol. A de novo synthesis of the anticancer natural product jaspine B was also achieved using a SDE-based approach.
Author: Joseph Ryan Cusick
Publisher:
ISBN:
Category : Allene
Languages : en
Pages : 398
Get Book Here
Book Description
Disclosed are studies on the structure and reactivity of allenes and spirodiepoxides (SDEs) and their application to synthesis. A novel ruthenium promoted cycloisomerization of [gamma]-enallenes to cyclopentenes was discovered. The effects of solvent, oxidant, and substrate structure on the stereoselectivity of SDE formation from 1,3-disubstituted and trisubstituted allenes were evaluated. A computational model was advanced for the rationalization of observed selectivity in such formations. The known acid instability of SDEs was exploited to effect a designed rearrangement of [beta]-silyl SDE to an [alpha]-hydroxy enone. Silyl-substituted SDEs were utilized to give carbinol substituted heterocycles with excellent ee, [alpha]-hydroxy enones, as well as [alpha], [beta]-dihydroxy olefins. A silyl-SDE approach was used to accomplish a short and efficient total synthesis of the natural product, epi-citreodiol. A de novo synthesis of the anticancer natural product jaspine B was also achieved using a SDE-based approach.
Author: Jennifer M. Schomaker
Publisher:
ISBN:
Category : Heterocyclic compounds
Languages : en
Pages : 668
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Many biologically active molecules contain three or more contiguous heteroatom stereocenters (`triads'), but rapid installation of these motifs can be a strategic challenge when one must consider the abundance of possible patterns and stereochemical configurations. In order to accomplish the synthesis of these motifs, we have focused our efforts to develop methods that allow rapid construction of heteroatom stereotriads from allenes. This was accomplished with bicylic methylene aziridine intermediates that are synthesized by an intramolecular metal catalyzed nitrene transfer reaction on an allene. In the first portion of this dissertation, the methylene aziridine's fate will follow an `electrophile then nucleophile' approach. In chapter 2, this strategy yields N,N,X spiroaminals from intermediate diazaspiro[2.2]pentane intermediates. Chapter 3 will focus on a unique rearrangement of these spiroaminals to yield N,O,N stereotriads. Chapter 4 will center on the synthesis of O,O,N stereotriads via dihydroxylation of the methylene aziridine. In our efforts to synthesize methylene aziridines, we found it increasingly difficult to control the outcome of nitrene transfer reactions. In the second portion of this thesis, Chapter 6, 7, and 8 will detail our efforts to control the selectivity of amination. Chapter 6 examines a method to control for C-H aminated allenes through substrate dependence by Rh catalyzed C-H amination of propargyl C-H bonds which can then be transformed into the desired allene. Chapter 7 will introduce a Ag nitrene transfer catalyst system that is capable of selective allene aziridination. The work in Chapter 8 then evolves this system by demonstrating that this Ag catalyst can be modified by adjustments in ligand stoichiometry. This simple alteration to the system reveals a catalyst that is capable of favoring the C-H insertion products over aziridine products. The consequence of these results gave rise to we now refer to as "dynamic catalysis". The last chapter of this thesis will delve into our attempts to synthesize the natural product jogyamycin with our allene fuctionalization protocols. These attempts demonstrate that our allene functionalization methods are viable for generating rapid and densely functionalized aminocyclopentitols, which will provide useful synthetically diversified variants of the jogyamycin core for biological evaluation.
Author: Andrei K. Yudin
Publisher: Wiley-VCH
ISBN: 352760748X
Category : Science
Languages : en
Pages : 516
Get Book Here
Book Description
Aziridines and epoxides are among the most widely used intermediates in organic synthesis, acting as precursors to complex molecules due to the strains incorporated in their skeletons. Besides their importance as reactive intermediates, many biologically active compounds also contain these three-membered rings. Filling a gap in the literature, this clearly structured book presents the much needed information in a compact and concise way. The renowned editor has succeeded in gathering together excellent authors to cover synthesis, applications, and the biological aspects in equal depth. Divided roughly equally between aziridines and epoxides, the twelve chapters discuss: * Synthesis of aziridines * Nucleophilic ring-opening of aziridines and epoxides * Organic synthesis with aziridine building blocks * Vinyl aziridines in organic synthesis * Diastereoselective aziridination reagents * Synthetic aspects of aziridinomitocene chemistry * Biosynthesis of biologically important aziridines * Organic catalysis of epoxide and aziridine ring formation * Metal-mediated synthesis of epoxides * Asymmetric epoxide ring opening chemistry * Epoxides in complex molecule synthesis * Biological activity of epoxide-containing molecules A high-quality reference manual for academic and industrial chemists alike.
Author: Kevin Sokol
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Elzbieta Wojaczynska
Publisher: John Wiley & Sons
ISBN: 3527349464
Category : Science
Languages : en
Pages : 692
Get Book Here
Book Description
Chiral Building Blocks in Asymmetric Synthesis A comprehensive introduction to the important classes of chiral building blocks Chirality — the asymmetric quality found in certain chemical compounds — plays an essential role in our world: chiral compounds can be found in biology, pharmaceutical compounds, agrochemicals, and fragrances. The stereoselective preparation of these complex molecular constructions constitutes a challenge. To this end, modern asymmetric synthesis utilizes a variety of valuable and efficient reagents employed as chiral auxiliaries, metal complexes and organocatalysts in stereoselective catalysis, and enantiopure reactants termed as chiral building blocks. In Chiral Building Blocks in Asymmetric Synthesis, the achievements in the fields of preparation of and applications of chiral blocks are presented. In doing so, the book comprehensively discusses the important classes of these reactants as the key for the asymmetric synthesis of chiral molecules. As such, it is an indispensable resource about synthetic methods, as well as possible modifications and transformations of important classes of chiral compounds. It also highlights the importance of their use as reactants and auxiliaries in the preparation of more sophisticated molecules or supramolecular systems. In Chiral Building Blocks in Asymmetric Synthesis readers will also find: Organization according to the most important compound classes — e.g. amino acids, BINOL and its derivatives, terpenes, and others — with an emphasis on synthesis and application A focus on the use of chiral building blocks for the preparation of bioactive compounds and supramolecular assemblies Chiral Building Blocks in Asymmetric Synthesis is a useful reference for organic chemists, catalytic chemists, chemists in industry, medicinal chemists, pharmaceutical chemists, and the libraries that support them.
Author: Montserrat Diéguez
Publisher: John Wiley & Sons
ISBN: 3527804072
Category : Technology & Engineering
Languages : en
Pages : 431
Get Book Here
Book Description
An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Author: Florencio Zaragoza Dörwald
Publisher: John Wiley & Sons
ISBN: 3527604987
Category : Science
Languages : en
Pages : 389
Get Book Here
Book Description
Most syntheses in the chemical research laboratory fail and usually require several attempts before proceeding satisfactorily. Failed syntheses are not only discouraging and frustrating, but also cost a lot of time and money. Many failures may, however, be avoided by understanding the structure-reactivity relationship of organic compounds. This textbook highlights the competing processes and limitations of the most important reactions used in organic synthesis. By allowing chemists to quickly recognize potential problems this book will help to improve their efficiency and success-rate. A must for every graduate student but also for every chemist in industry and academia. Contents: 1 Organic Synthesis: General Remarks 2 Stereoelectronic Effects and Reactivity 3 The Stability of Organic Compounds 4 Aliphatic Nucleophilic Substitutions: Problematic Electrophiles 5 The Alkylation of Carbanions 6 The Alkylation of Heteroatoms 7 The Acylation of Heteroatoms 8 Palladium-Catalyzed C-C Bond Formation 9 Cyclizations 10 Monofunctionalization of Symmetric Difunctional Substrates
Author: Xiao-Feng Wu
Publisher: John Wiley & Sons
ISBN: 352734196X
Category : Science
Languages : en
Pages : 552
Get Book Here
Book Description
Written by highly renowned and experienced authors, this is the only reference on the application of solvents as reagents. Clearly structured, the text describes various methods for the activation and reaction of these small molecules, highlighting the synthetic opportunities as well as process-oriented advantages. To this end, all relevant types of solvents are covered separately and emphasized with numerous synthetic examples, while taking care to explain applications so as to avoid undesired side reactions. The result is a unique resource for every synthetic chemist and reaction engineer in industry and academia working on the methodical optimization of synthetic transformations.
Author: D. M. P. Mingos
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 976
Get Book Here
Book Description
Provides essential information for any chemist or technologist who needs to use or apply organometallic compounds. Provides a comprehensive overview of recent developments in the field and attempts to predict trends in the field over the next ten years.
