Download or read book Donor Acceptor Cyclopropanes in Organic Synthesis written by Prabal Banerjee and published by John Wiley & Sons. This book was released on 2024-02-09 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Donor-Acceptor Cyclopropanes in Organic Synthesis Facilitate milder, simpler reactions in organic synthesis with this cutting-edge family of building blocks Donor-Accepted Cyclopropanes, or DACs, have attracted a resurgence of interest from organic chemists in recent decades for their role in facilitating various reactions such as cycloadditions, annulations, ring-opening and enantioselective transformations. The structural arrangement of DACs leads to milder, simpler reaction conditions, which have made them indispensable for a range of fundamentally and industrially important processes. Donor-Acceptor Cyclopropanes in Organic Synthesis covers comprehensively the chemistry and applications of this compound class. The result is an invaluable guide for any researcher looking to bring DACs to bear in their own areas of research or development. Readers will also find: A brief introduction of the history and reactivity of DACs Detailed discussion of reactions including Lewis acid-catalyzed cycloadditions, metal-free activation, asymmetric transformations, organocatalysis, and many more Application of DACs in natural product synthesis and pharmaceutical/agrochemical research Donor-Acceptor Cyclopropanes in Organic Synthesis is ideal for organic chemists, experts in catalysis, pharmaceutical researchers, and any other scientists interested in facilitating milder, simpler reactions.
Download or read book Studies in Acceptor acceptor donor Cyclopropanes written by Yahaira De Bary Reyes and published by . This book was released on 2014 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Isolated from Spongosorites sp., Dragmacidin E is of synthetic interest due to its biological properties and novel molecular structure. A promising therapeutic target, its synthetic challenge is attributed to its heptacyclic core. In this study, we propose the synthesis of a Dragmacidin E heptacyclic core precursor, mediated through a Lewis acid (LA) mediated cyclization of an acceptor-acceptor-donor (AAD) cyclopropane. Utilizing a model study, alkoxy AAD cyclopropanes were investigated to develop a protocol for precursor synthesis. After generating various ethyl-a-diazobenzoyl acetate derivatives, the metal catalyzed cyclopropanation reaction of these compounds was studied. With vinyl acetate and Rh2esp2, acetoxy AAD cyclopropanes were synthesized in yields ranging from 12 % - 53 %. These cyclopropanes were successfully generated and rearrangement into dihydrofuran products was avoided. To complete our model study, LA cyclization of acetoxy AAD cyclopropanes was studied. Using stoichiometric quantities of TiCl4, naphthol derivatives were synthesized in one step.
Download or read book Mechanistic Studies of Donor acceptor Cyclopropanes written by Tristan Chidley and published by . This book was released on 2015 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclopropane 1,1-diesters have been investigated as a source of donor-acceptor cyclopropanes, providing an understanding of the mechanism of reaction between these cyclopropanes and nitrosoarenes, as well as azo dicarboxylates. Cross-over experiments have been utilized to provide key pieces of experimental evidence that help generate a theoretical model of the reactions. By understanding these reactions with precision, the avenue to expand the reaction scope and develop other useful reactions is opened up. This allows the chemistry to be better utilized, providing easier access to important molecules when needed, and contributes to advancing the field of synthetic organic chemistry. In addition, cyclobutane 1,1-diesters were also investigated as a source of donor-acceptor cyclobutanes. Specifically, their use in cycloaddition reactions has been developed to include the reaction of cyclobutanes with cis-diazenes, providing access to hexahydropyridazines. These compounds are synthesized in an efficient manner and are known to contain biologically active properties.
Download or read book Reactivity Studies of Donor Acceptor Cyclopropanes written by Alexander Kreft and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Reactivity of a Novel Donor acceptor Cyclopropane written by Xiaomei Zheng and published by . This book was released on 2006 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Donor acceptor Cyclopropanes in Natural Product Synthesis written by Cheryl Ann Carson and published by . This book was released on 2009 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Total Synthesis of goniomitine Via a 3 2 Cyclization with Donor acceptor Cyclopropane written by Christian Leonardo Morales and published by . This book was released on 2007 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dienamine Catalysis for Organic Synthesis written by Kengadarane Anebouselvy and published by Royal Society of Chemistry. This book was released on 2018-03-02 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book New Chemistry of Donor acceptor Cyclopropanes written by Ming Yu and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthetic Applications and Methodological Developments of Donor Acceptor Cyclopropanes written by Alexander F. G. Goldberg and published by . This book was released on 2013 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Samarium II Iodide induced Ring Openings and Donor acceptor Cyclopropanes written by Elizabeth Anne Lund and published by . This book was released on 1994 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unprecedented ring opening reactions of $\alpha$-ketospirocyclobutanes 123 and 124 with SmI$\sb2$ afforded ketones 126 and 127 in 70% and 88% yield, respectively.
Download or read book Exploring the Reactivity of Donor acceptor Cyclopropanes and the Synthesis of Quebrachamine written by Huck K. Grover and published by . This book was released on 2014 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development and utility of cyclopropanes is an ever-growing field within organic chemistry. In particular, donor-acceptor cyclopropanes have been used in a vast array of methods to access a variety of different hetero and carbocyclic molecular scaffolds. Recently, we have developed a Zn(NTf2)2 catalyzed tandem reaction consisting of a nucleophilic ringopening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure, resulting in the efficient one-step synthesis of tetrahydrocarbazoles. These adducts may be further elaborated to carbazoles. The scope and limitations of this method were determined along with a mechanistic study into the function of the zinc catalyst. In an expansion of our work with 1,1-cyclopropanediesters, we have explored the reactivity and utilization of hemimalonate cyclopropanes. To this end, we have developed two unique methods exploring the self-activating nature of these cyclopropanes under catalyst free conditions. Cyclopropane hemimalonates, when treated with sodium azide, undergo a tandem ring-opening decarboxylation to produce?-azidobutyric acids in good yields. These adducts were hydrogenated to form?-aminobutyric acid (GABA) methyl esters. Additionally, cyclopropane hemimalonates have led to the facile synthesis of?-substituted butanolides. Under microwave irradiation, cyclopropane hemimalonates undergo rapid conversion to butanolides in the presence of inorganic salts with an unprecedented retention of stereochemistry. This unique process, in conjunction with a newly developed crossmetathesis method, has been applied to the total synthesis of the naturally occurring, (R)- dodecan-4-olide. Finally, recent efforts to develop a unified approach to piperidine-containing indole natural products have shown great promise. A preliminary investigation into the prospect of a common synthetic intermediate for the synthesis of a variety of indole alkaloids has led to a synthesis of substituted piperidinones and the corresponding piperidines. These common natural product cores are accessed via a reductive amination/lactamization sequence of dimethyl 3-ethyl-3-formylpimelate. The synthetic utility of this initial study has been displayed in the formal synthesis of (+/- )-quebrachamine.
Download or read book The Application of Novel Donor Acceptor Cyclopropanes in the Synthesis of Linearly Fused Tricyclic Triazoles written by Michelle Elaine Flisar and published by . This book was released on 2014 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous work in the Kerr group has shown the su ccess of donor-acceptor cyclopropanes as substrates in a variety of synthetic reactions; this document will apply the use of donor acceptor cyclopropanes in various synthetic reactions. This was done using a 2-substituted 1,1 - cyclopropanediester, in the Overman Rearrangement, which has yet to be explored using DA cyclopropanes. Another useful DA cyclopropane is the novel a cetylene-bearing donor acceptor diester cyclopropanes which would be synthetically useful in a wide variety of reactions. In particular, the Conia-ene cyclization occurred intramolecularly with this alkyne DA cyclopropane with a large library of nucleophiles. Finally, taking this acetylene-bearing DA cyclopropane, it was converted to the hemimalonate version, and subjected to a ring-opening by azide as the nucleophile to generate an alkyl azide; which then underwent a [3+2] dipolar cycloaddition with the alkyne to form novel linearly fused tricyclic triazoles.
Download or read book Studies of Donor acceptor Complexes written by Larry Marlin Julien and published by . This book was released on 1966 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cyclopropanes in Organic Synthesis written by Oleg G. Kulinkovich and published by John Wiley & Sons. This book was released on 2015-09-30 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a practical guidebook about cyclopropanes that thoroughly surveys derivatives and transformations, synthetic methods, and experimental efficiency as a gateway for further research and development in the field. • Provides comprehensive lists and synthetically-oriented synopses of cyclopropane chemistry review references along with publication data on applications in the syntheses of natural and related biologically active compounds • Acts as a resource to help readers better understand cyclopropane applications for the efficient realization of synthetically important organic transformations and popular experimental procedures • Includes new developments and up-to-date information that will lead to original methodologies for complex organic synthesis • Stresses universality, flexibility, and experimental efficiency of a strategy based on preparing cyclopropane derivatives and performing ring cleavage reactions with inexpensive reagents • Focuses on the synthetic potential of cyclopropane applications, for example the synthesis of natural compounds and other target-oriented syntheses via cyclopropane intermediaries, as well on their planning by retrosynthetic analysis
Download or read book Synthesis and Reactivity of Donor Acceptor Substituted Aminocyclopropanes and Aminocyclobutanes written by Florian de Nanteuil and published by Springer. This book was released on 2015-09-26 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a general approach to accessing nitrogen-substituted hetero- and carbocycles. In short, the annulation reactions developed in the thesis make it possible to access nitrogen-substituted four-, five- and six-membered rings, all essential building blocks for the synthesis of bioactive molecules. Many natural products display a saturated polycyclic core allowing a well-defined arrangement of functional groups in space. As such, they can interact with biological targets with a high degree of affinity and selectivity, surpassing many synthetic drugs. Nevertheless, the efficient synthesis of such complex ring systems poses a challenge for organic chemistry. Through careful tuning of the electronic properties of a nitrogen donor group and a diester acceptor group, the first [3+2] annulation reaction between aminocyclopropanes and enol ethers or carbonyl compounds is now possible. The reaction proceeded under mild catalytic conditions, and the building blocks obtained can be found at the core of bioactive alkaloids, drugs such as Ramipril and biomolecules such as DNA and RNA. Thanks to the dynamic kinetic asymmetric annulation of aminocyclopropanes with enol ethers and aldehydes, access to enantioenriched compounds is also now possible. Lastly, a synthesis of donor-acceptor aminocyclobutanes via [2+2] cycloaddition using a cheap iron catalyst was developed, allowing them to be used in [4+2] annulations to access cyclohexylamines.
Download or read book Reactions of Donor acceptor Cyclopropanes with Chalcogen and Pnictogen rich Species written by Gwyndaf Alun Oliver and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
