Development of New Gold-catalyzed Strategies in N-acyliminium Ion Chemistry

Development of New Gold-catalyzed Strategies in N-acyliminium Ion Chemistry
Author: Malina Michalska
Publisher:
Total Pages: 68
Release: 2013
Genre:
ISBN:
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The research project is centred on the development of new gold catalyzed transformations in N-acyliminium ion chemistry. The objective of our first part of the project is to develop an enantioselective gold-catalyzed 5 exo-dig intramolecular hydroalkoxylation/aza-Ferrier-Petasis rearrangement sequence. This sequence could give an asymmetric and atom economic expeditious access to the structure of hydropyrrolizidines, which are known to be potential biologically active compounds. A second part of the project is devoted to the development of the first catalytic alkynylation of cyclic N-acyliminium ions using N,O-acetals. This type of reaction is potentially an important transformation, giving rise to propargylic amine derivatives amenable to further interesting synthetic manipulations en route to nitrogen-containing natural products and some analogs. Considering our objectives, key features is the use of TMS alkynes in conjunction with gold complexes that have been paired with poorly nucleophilic counter-ions. To broaden the scope of catalysis based on gold, it is important to extend the range of substrates and functional groups that can be activated by gold complexes. A final section is devoted to the sequential catalysis which designs the promotion of catalytic multistep processes. In this way, two fundamentally distinct chemical transformations are catalytically promoted in a single flask. This research area allows the rapid and efficient reach of complex molecular frameworks with improved yields and resource efficiency. Therefore, this is an exciting theme in modern organic synthesis that has recently stimulated the report of numerous excellent contributions.

Modern Gold Catalyzed Synthesis

Modern Gold Catalyzed Synthesis
Author: A. Stephen K. Hashmi
Publisher: John Wiley & Sons
Total Pages: 419
Release: 2012-05-21
Genre: Science
ISBN: 3527319522
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With its impressive features, gold has led to completely new reaction types in recent years, which in turn have strongly influenced both organic catalysis and material science. Other fields where a significant amount of new results has been obtained include nanotechnology, self assembly/supramolecular systems and biochemical/medicinal chemistry. As a result, gold is one of the hottest topics in catalysis at the moment, with an increasing amount of research being carried out in this field. While focusing on homogeneous catalysis, this monograph also covers the main applications in heterogeneous catalysis. Following a look at the gold-catalyzed addition of heteroatom nucleophiles to alkynes, it goes on to discuss gold-catalyzed additions to allenes and alkenes, gold-catalyzed benzannulations, cycloisomerization and rearrangement reactions, as well as oxidation and reduction reactions. The whole is finished off with a section on gold-catalyzed aldol and related reactions and the application of gold-catalyzed reactions to natural product synthesis. Of interest to synthetic chemists and inorganic chemists, as well as organic chemists working in homogeneous catalysis, physical and technical chemists.

Gold Catalysis: An Homogeneous Approach

Gold Catalysis: An Homogeneous Approach
Author: Veronique Michelet
Publisher: World Scientific
Total Pages: 564
Release: 2014-06-20
Genre: Science
ISBN: 1783265558
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Research on designing new catalytic systems has been one of the most important fields in modern organic chemistry. One reason for this is the predominant contribution of catalysis to the concepts of atom economy and green chemistry in the 21st century. Gold, considered catalytically inactive for a long time, is now a fascinating partner of modern chemistry, as scientists such as Bond, Teles, Haruta, Hutchings, Ito and Hayashi opened new perspectives for the whole synthetic chemist community. This book presents the major advances in homogeneous catalysis, emphasizing the methodologies that create carbon-carbon and carbon-heteroatom bonds, the applications that create diversity and synthesize natural products, and the recent advances and challenges in asymmetric catalysis and computational research.It provides readers with in-depth information about homogeneous gold-catalyzed reactions and presents several explanations for the scientific design of a catalyst. Readers will be able to understand the entire gold area and find solutions to problems in catalysis.Gold Catalysis — An Homogeneous Approach is part of the Catalytic Science Series and features prominent authors who are experts in their respective fields.

Development of Gold-catalyzed Insertions Into Unactivated Aliphatic C-H Bonds

Development of Gold-catalyzed Insertions Into Unactivated Aliphatic C-H Bonds
Author: Youliang Wang
Publisher:
Total Pages: 241
Release: 2016
Genre:
ISBN: 9781369340693
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Despite the tremendous advance in homogeneous gold catalysis in the past decade or so, the functionalization of unactivated C(sp3)-H bonds, a highly desirable and yet challenging streamlining synthetic strategy, has so far rarely been realized in this 'gold rush'. My graduate work was focused on the development of new strategies of gold catalysis to access highly reactive gold intermediates and harness their reactivities in insertion into unactivated C(sp3)-H bonds. Three approaches are discussed in this dissertation: (1) via gold vinylidenes: fully functionalized gold vinylidenes generated from simple TMS-terminated alkynones facilely insert into unactivated alkyl groups to furnish versatile 2-bromocyclopentenones; (2) via 'gold benzyne': gold-catalyzed cycloisomerizations of enediynes provide access to hypothetical 'gold benzyne' species, which exhibit reactivities distinctively different from transition metal-free benzynes, including insertions into unactivated C(sp3)-H bonds and regiospecific nucleophilic additions; (3) via oxidatively generated gold carbene: gold carbenes generated upon the oxidation of alkynones are demonstrated for the first time to be capable of inserting into unactivated C(sp 3)-H bonds to yield cylcopentanones and cyclobutanones.

New Gold-Catalyzed Reactions and Applications for the Synthesis of Alkaloids

New Gold-Catalyzed Reactions and Applications for the Synthesis of Alkaloids
Author: Ana Escribano Cuesta
Publisher: Springer
Total Pages: 0
Release: 2013-08-21
Genre: Science
ISBN: 9783319007014
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Ana Escribano Cuesta's thesis presents a detailed study of the inter- and intramolecular reactions of carbonyl compounds with 1,6-enynes using gold (I) complexes. An important part of the work involved streamlining the variables that allow the selective synthesis of different products such as tricyclic compounds, dihydropyrans, 1,3-dienes or cyclobutenes. The second chapter highlights the importance and difficulties in synthesising a cyclobutene subunit and the author includes a detailed description of how the products were prepared. The final chapter outlines the synthesis of lundurines using methodology developed by the author's research group for intramolecular gold-catalyzed cyclization of indoles with alkynes. The lundurine products developed in this work show significant in vitro cytoxicity toward B16 melanoma cells. The work in this thesis has led to a number of publications in high-profile chemistry journals.

Gold Catalysis

Gold Catalysis
Author: F. Dean Toste
Publisher:
Total Pages: 564
Release: 2014-08-01
Genre: Catalysis
ISBN: 9781848168534
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Research on designing new catalytic systems has been one of the most important fields in modern organic chemistry, and one reason for this is the predominant contribution of catalysis to the concepts of atom economy and green chemistry in the 21st century. Gold, considered catalytically inactive for a long time, is now a fascinating partner of modern chemistry, as scientists such as Bond, Haruta, Hutchings, Ito and Hayashi opened new perspectives for the whole synthetic chemist community. This book presents the major advances in homogeneous catalysis, emphasizing the methodologies that create carbon-carbon and carbon-heteroatom bonds, the applications that create diversity and synthesize natural products, and the recent advances and challenges in asymmetric catalysis and computational research. The Handbook of Homogeneous Gold Catalysis provides readers with in-depth information about gold-catalyzed reactions and presents several explanations for the scientific design of a catalyst. Readers will be able to understand the entire gold area and find solutions to problems in catalysis. Featuring prominent authors, who are experts in their respective fields, this is the first book dedicated to homogeneous gold chemistry. Contents: From Gold in Nature to Gold Catalysts (S Kramer and F Gagosz); Oxidation and Reduction Reactions (L Zhang); Gold-Catalyzed Addition of Carbon Nucleophile to C-C Multiple Bond (B Simmons and H C Shen); Gold-Catalyzed Addition of Heteroatom Nucleophile to C-C Multiple Bond (N Asao, N Hatakeyama and Y Yamamoto); Gold-Catalyzed Synthesis of Heterocycles (A Arcadi); Multi-Component Reactions (R Skouta and C J Li); Gold Catalyzed Tandem and Cascade Reactions (R-S Liu); Cycloisomerization Reactions of 1, n -Enynes (N Huguet and A Echavarren); Gold-Catalyzed Reaction of Propargylic Esters (L Fensterbank, J-P Goddard, M Malacria and S Simonneau); Gold-Catalyzed Cross-Coupling Reactions (S Blum); Gold-Catalyzed Reactions: A Computational Approach (E Soriano & J Marco-Contelles); Asymmetric Gold-Catalyzed Reactions (P Y Toullec, A Pradal and V Michelet); Gold Catalysis in Natural Product Synthesis (M Gesinski and F D Toste). Readership: Student, professionals.

Catalysis by Gold

Catalysis by Gold
Author: Geoffrey Colin Bond
Publisher:
Total Pages: 366
Release: 2006-01-01
Genre: Science
ISBN: 1860946585
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Gold has traditionally been regarded as inactive as a catalytic metal. However, the advent of nanoparticulate gold on high surface area oxide supports has demonstrated its high catalytic activity in many chemical reactions. Gold is active as a heterogeneous catalyst in both gas and liquid phases, and complexes catalyse reactions homogeneously in solution. Many of the reactions being studied will lead to new application areas for catalysts by gold in pollution control, chemical processing, sensors and fuel cell technology. This book describes the properties of gold, the methods for preparing gold catalysts and ways to characterise and use them effectively in reactions. The reaction mechanisms and reasons for the high activities are discussed and the applications for gold catalysis considered.

Expanding the Frontier of Gold-catalyzed Cyclizations and Rational Ligand Design

Expanding the Frontier of Gold-catalyzed Cyclizations and Rational Ligand Design
Author: Deepika Malhotra
Publisher:
Total Pages: 213
Release: 2014
Genre: Catalysts
ISBN:
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The focus of my dissertation work is to study the gold-catalyzed intramolecular and intermolecular cyclizations involving oxonium intermediates towards the application of synthetically interesting frameworks under ambient conditions and developing a rational approach for the effective catalyst design in gold catalysis. We explored the goldcatalyzed oxygen-transfer reactions of 2-alkynyl-1,5-diketones or 2-alkynyl-5-ketoesters to furnish five-membered rings bearing a quaternary carbon tethered to a carbonyl group. The detailed mechanistic investigation on the newly proposed intramolecular [4+2] cycloaddition mechanism was performed by means of isotopic experiments and quantum chemical calculations. The reactivity of alkynylenolate was investigated in the reactions of allenic ketones and vinyl ketones which led to versatile syntheses of 2-alkynyl-1,5-diketones, 4-alkynyl-3-hydroxycyclohexones and 4-alkynylcyclohexenones. We also investigated the gold-catalyzed annulations of 2-alkynyl benzaldehyde with acyclic or cyclic vinyl ethers under very mild conditions, and successfully developed synthetically interesting dihydronaphthalenes, acetal-tethered isochromenes and bicyclo[2.2.2]octane derivatives often found in biologically active molecules and natural products. Although there have been numerous reviews and publications on new gold-catalyzed transformations, the development of new catalysts still relies on a hit-and-miss approach. Because the decay of the active cationic gold catalyst is the main reason for the high catalytic loading required for the majority of gold-catalyzed transformations, we developed a modular approach for effective catalyst design in gold catalysis. We discovered a new phosphine-based precatalyst that is broadly applicable and highly efficient - in the parts per million (ppm) range - at room temperature or slightly elevated temperatures (

Gold And Silver Co-Operative Catalysis For Carbon Bond Formation

Gold And Silver Co-Operative Catalysis For Carbon Bond Formation
Author: Pradp Bgle
Publisher:
Total Pages: 0
Release: 2023-09-14
Genre: Technology & Engineering
ISBN: 9785891842199
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This book is a comprehensive guidebook that covers the recent advances in gold and silver co-operative catalysis for carbon-carbon and carbon-heteroatom bond formation. The use of gold and silver in catalysis has revolutionized the field of organic synthesis, allowing for the development of new reactions and strategies that were previously inaccessible. The Book provides an in-depth discussion of the various gold and silver co-operative catalysis strategies and their application in the synthesis of a wide range of organic molecules, including pharmaceuticals, natural products, and materials. The author describes the key steps involved in these reactions, including the design of suitable catalysts, optimization of reaction conditions, and purification of the products. Also covers the use of gold and silver co-operative catalysis in the synthesis of other important compounds such as heterocycles, carbenes, and vinylidene complexes. The author discusses the advantages and limitations of gold and silver co-operative catalysis compared to other catalytic systems and provides practical guidance for researchers interested in using these catalysts in their own synthetic projects. Overall, "Gold and Silver Co-Operative Catalysis for Carbon Bond Formation" is an essential reference for synthetic chemists, medicinal chemists, and material scientists who are interested in the development of new catalytic systems for carbon-carbon and carbon-heteroatom bond formation using gold and silver co-operative catalysis.