Pd-H/Lewis base cooperative catalysis confers asymmetric allylic alkylation of esters atom-economy and stereodivergence
Pd-H/Lewis base cooperative catalysis confers asymmetric allylic alkylation of esters atom-economy and stereodivergence

Author: Mostafa Sayed

Publisher: OAE Publishing Inc.

Published: 2023-04-20

Total Pages: 6

ISBN-13:

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The construction of Csp3-Csp3 with high stereoselectivity, even in a stereodivergent way, has been a long-standing theme in organic synthesis. As an atom- and step-economic transformation, transition metal hydride-mediated allylic alkylation of enolizable carbonyl compounds with readily available allenes, alkynes or 1,3-dienes as the unconventional allylating reagents has recently emerged as a promising protocol for the stereoselective construction of Csp3-Csp3 bonds with high efficiency. Due to their less enolizability and weak nucleophilicity, simple esters remain challenging substrates for these coupling reactions. On the other hand, the strategy of metal/organo combined catalysis has recently emerged as one of the wide-ranging disciplines and powerful tools in asymmetric synthesis. Considering the recent achievements of chiral Lewis base catalysis in catalytic asymmetric α-functionalization of esters through a “rebound” mechanism, the cooperative combination of chiral Lewis bases and metal hydride catalysis may offer great opportunities to the aforementioned chemistry. Recently, the groups of Snaddon and Zi have made remarkable progresses in this area through palladium and chiral Lewis base cooperative catalysis.

Stereocontrolled Cooperative Catalysis in Allylic Functionalization
Stereocontrolled Cooperative Catalysis in Allylic Functionalization

Author: Smita Mandal

Publisher:

Published: 2024

Total Pages: 0

ISBN-13:

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Organofluorine compounds have witnessed significant applications in agrochemical, pharmaceutical industries, and material science. As a result, progress in developing synthetic methods to prepare fluorinated compounds has been rapid. However, general methods for preparing enantioenriched tertiary alkyl fluoride motifs are rare, as such motifs present numerous challenges for both catalysis and stereocontrol. We have demonstrated catalytic asymmetric a-functionalization of a-fluoro acyclic esters by the union of C1-ammonium enolates generated using Lewis base catalyst with pi-(allyl)Ir(III) electrophiles to furnish allylated products with two vicinal stereogenic centers. The configuration of each stereogenic center is controlled independently via a cooperative catalysis platform giving access to the stereodivergent construction of tertiary fluorides. The direct employment of nonstabilized nucleophiles in Pd-catalyzed asymmetric allylic alkylation poses a significant synthetic challenge. We have embraced photoredox/transition metal cooperative catalysis to address this limitation, which offers an alternative approach by unlocking one-electron reaction pathways. However, the control of regioselectivity in such a reaction framework is predominantly determined by the nature of the substituents, where the nucleophile preferentially attacks the allylic carbon with an ‘aryl substituent’. However, access to valuable aliphatic bearing stereocenters is desirable but impossible using existing synthetic protocols. Encouraged by our previous success exploiting substituents on the regioselectivity of nucleophilic attack on pi-(allyl)Pd species, we conceived of a general approach to forge asymmetric C(sp3)-C(sp3) bond formation by leveraging the powerful directing effect of synthetically versatile silicon substituents. Here, the well-established radical precursor 4-alkyl-1,4- dihydropyridine was employed which when irradiated by blue LEDs, generates the desired alkyl radical which then couples with silicon-substituted pi-(allyl)Pd complex to furnish the desired product after reductive elimination.

Artificial Metalloenzymes and MetalloDNAzymes in Catalysis
Artificial Metalloenzymes and MetalloDNAzymes in Catalysis

Author: Montserrat Diéguez

Publisher: John Wiley & Sons

Published: 2018-02-21

Total Pages: 431

ISBN-13: 3527804072

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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.

Asymmetric Organocatalysis Combined with Metal Catalysis
Asymmetric Organocatalysis Combined with Metal Catalysis

Author: Bruce A. Arndtsen

Publisher: Springer Nature

Published: 2020-04-24

Total Pages: 211

ISBN-13: 3030438511

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The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience.Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.The chapter "Enamine/Transition Metal Combined Catalysis: Catalytic Transformations Involving Organometallic Electrophilic Intermediates" is available open access under a CC BY 4.0 License via link.springer.com.

Multicomponent Reactions in Organic Synthesis
Multicomponent Reactions in Organic Synthesis

Author: Jieping Zhu

Publisher: John Wiley & Sons

Published: 2015-02-09

Total Pages: 512

ISBN-13: 3527332375

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Comprehensive and up-to-date, this book focuses on the latest advances in the field, such as newly developed techniques, more environmentally benign processes, broadened scopes, and completely novel MCRs. In addition to carbene-promoted MCRs and frequently applied metal-catalyzed MCRs, it also covers recently developed catalytic enantioselective variants as well as MCR in drug discovery and for the synthesis of heterocyclic molecules and macrocycles. Edited by the leading experts and with a list of authors reading like a "who's who" in multicomponent reaction chemistry, this is definitely a must-have for every synthetic organic chemist as well as medicinal chemists working in academia and pharmaceutical companies.

Enantioselective Organocatalysis
Enantioselective Organocatalysis

Author: Peter I. Dalko

Publisher: John Wiley & Sons

Published: 2007-06-27

Total Pages: 559

ISBN-13: 3527610952

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In this reference leaders at the forefront of research provide an insight into one of the hottest topics in organic synthesis, focusing on the most important enantioselective reactions. Clearly structured, each entry begins with a concise introduction, including a mechanistic discussion of the reaction, followed by preparative guidelines for newcomers, such as carefully selected working procedures with critical notes for bench chemists, rules of thumb and tips and tricks.

Homogeneous Gold Catalysis
Homogeneous Gold Catalysis

Author: LeGrande M. Slaughter

Publisher: Springer

Published: 2015-03-30

Total Pages: 292

ISBN-13: 3319137220

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The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field. Review articles for the individual volumes are invited by the volume editors. Readership: research chemists at universities or in industry, graduate students.

Fluorine-containing Amino Acids
Fluorine-containing Amino Acids

Author: Valery P. Kukhar

Publisher: John Wiley & Sons

Published: 1995-04-06

Total Pages: 432

ISBN-13:

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In recent years, organo-fluorine chemistry has made a marked impact on the design and synthesis of a large variety of biologically active molecules, such as steroids, carbohydrates, amines, amino acids, peptides and other natural products. Naturally occurring amino acids play a pivotal role in living systems, and therefore synthetic fluorine-containing amino acids have been of significant interest to researchers working towards the understanding and modification of physiological processes. Fluorine-containing Amino Acids: is the first volume devoted to the synthesis and properties of fluorine-containing amino acids pays special attention to the preparation of enantiomerically pure acids (which are essential to the modern pharmaceutical industry) deals with a rapidly expanding field of research has been written by experienced researchers who are responsible for many developments in the field highlights the interdisciplinary nature of this topic Fluorine-containing Amino Acids is the only dedicated reference in this subject and will be essential for researchers in synthetic organic, peptide, natural product, and medicinal chemistry and biochemistry.

Antimicrobials
Antimicrobials

Author: Flavia Marinelli

Publisher: Springer Science & Business Media

Published: 2013-10-04

Total Pages: 363

ISBN-13: 3642399681

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Reports on the emergence and prevalence of resistant bacterial infections in hospitals and communities raise concerns that we may soon no longer be able to rely on antibiotics as a way to control infectious diseases. Effective medical care would require the constant introduction of novel antibiotics to keep up in the “arms race” with resistant pathogens. This book closely examines the latest developments in the field of antibacterial research and development. It starts with an overview of the growing prevalence of resistant Gram-positive and Gram-negative pathogens, including their various resistance mechanisms, prevalence, risk factors and therapeutic options. The focus then shifts to a comprehensive description of all major chemical classes with antibacterial properties, their chemistry, mode of action, and the generation of analogs; information that provides the basis for the design of improved molecules to defeat microbial infections and combat the emerging resistances. In closing, recently developed compounds already in clinical use, those in preclinical or first clinical studies, and a number of promising targets to be exploited in the discovery stage are discussed.

Catalytic Asymmetric Synthesis
Catalytic Asymmetric Synthesis

Author: Takahiko Akiyama

Publisher: John Wiley & Sons

Published: 2022-05-27

Total Pages: 798

ISBN-13: 1119736412

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Catalytic Asymmetric Synthesis Seminal text presenting detailed accounts of the most important catalytic asymmetric reactions known today This book covers the preparation of enantiomerically pure or enriched chemical compounds by use of chiral catalyst molecules. While reviewing the most important catalytic methods for asymmetric organic synthesis, this book highlights the most important and recent developments in catalytic asymmetric synthesis. Edited by two well-qualified experts, sample topics covered in the work include: Metal catalysis, organocatalysis, photoredox catalysis, enzyme catalysis C–H bond functionalization reactions Carbon–carbon bond formation reactions, carbon–halogen bond formation reactions, hydrogenations, polymerizations, flow reactions Axially chiral compounds Retaining the best of its predecessors but now thoroughly up to date with the important and recent developments in catalytic asymmetric synthesis, the 4th edition of Catalytic Asymmetric Synthesis serves as an excellent desktop reference and text for researchers and students, from upper-level undergraduates all the way to experienced professionals in industry or academia.