C(sp2)-C(sp3) Cross-coupling of Aryl Halides and Active C(sp3)-H Bonds Via Dual Catalysis PDF Download
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Author: Nicholas Armada
Publisher:
ISBN:
Category :
Languages : en
Pages : 51
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Book Description
Convenient catalytic methodologies that can facilitate the formation of C-C bonds are undoubtedly of great interest in synthetic organic chemistry. Recent reports in literature have showcased hybrid catalytic methods that couple Ni-redox catalysis and photocatalysis to enable C-H activation of tetrahydrofuran (THF) and subsequent cross-coupling with aryl halides in appreciable yields and under relatively mild reaction conditions.1-2 However, these studies used expensive, heavy metal-containing photocatalysts and both report difficulty obtaining low-specificity across their scopes of aryl-halides. The following report will shed light on a class of photo-excitable small organic molecules that – in conjunction with a catalytic Ni-redox cycle – can be used to catalyze C-C cross-coupling reactions between THF and aryl chlorides, bromides, and iodides with yields comparable to the aforementioned reports. After screening several organic molecules with suspected photoactivity and optimization of the reaction conditions, several benzophenone derivatives were found to catalyze the cross-coupling reaction in yields up to 97%. Mechanistic investigations suggest that this reaction proceeds through a tandem catalytic pathway that involves a photocatalyzed hydrogen atom transfer/proton-coupled electron transfer (HAT/PCET) process and a Ni-mediated oxidative addition/reductive elimination cross-coupling process.
Author: Nicholas Armada
Publisher:
ISBN:
Category :
Languages : en
Pages : 51
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Book Description
Convenient catalytic methodologies that can facilitate the formation of C-C bonds are undoubtedly of great interest in synthetic organic chemistry. Recent reports in literature have showcased hybrid catalytic methods that couple Ni-redox catalysis and photocatalysis to enable C-H activation of tetrahydrofuran (THF) and subsequent cross-coupling with aryl halides in appreciable yields and under relatively mild reaction conditions.1-2 However, these studies used expensive, heavy metal-containing photocatalysts and both report difficulty obtaining low-specificity across their scopes of aryl-halides. The following report will shed light on a class of photo-excitable small organic molecules that – in conjunction with a catalytic Ni-redox cycle – can be used to catalyze C-C cross-coupling reactions between THF and aryl chlorides, bromides, and iodides with yields comparable to the aforementioned reports. After screening several organic molecules with suspected photoactivity and optimization of the reaction conditions, several benzophenone derivatives were found to catalyze the cross-coupling reaction in yields up to 97%. Mechanistic investigations suggest that this reaction proceeds through a tandem catalytic pathway that involves a photocatalyzed hydrogen atom transfer/proton-coupled electron transfer (HAT/PCET) process and a Ni-mediated oxidative addition/reductive elimination cross-coupling process.
Author: Aiwen Lei
Publisher: John Wiley & Sons
ISBN: 3527336885
Category : Technology & Engineering
Languages : en
Pages : 243
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Book Description
The first handbook on this emerging field provides a comprehensive overview of transition metal-catalyzed coupling reactions in the presence of an oxidant. Following an introduction to the general concept and mechanism of this reaction class, the team of authors presents chapters on C-C cross-coupling reactions using organometallic partners, C-Heteroatom bond forming reactions via oxidative couplings, and C-H couplings via C-H activation. The text also covers such groundbreaking topics as recent achievements in the fields of C-C and C-X bond formation reactions as well as C-H activation involving oxidative couplings. With its novel and concise approach towards important building blocks in organic chemistry and its focus on synthetic applications, this handbook is of great interest to all synthetic chemists in academia and industry alike.
Author: Xiao-Feng Wu
Publisher: Springer Nature
ISBN: 3031328671
Category : Science
Languages : en
Pages : 403
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Book Description
This volume presents recent progress on 3d base metal catalyzed C-C cross coupling reactions. The contributions provide detailed discussions on the use of cheap metal catalysts such as Cr, Mn, Fe, Co, Ni, Cu, and Zn to construct Csp2-Csp2, Csp2-Csp3 and Csp3-Csp3 bonds with a variety of substrates. These non-noble metal catalyst have many advantages such as being inexpensive, having low toxicity and are environmentally benign. Therefore the use of cheap metal catalysts in organic synthesis has gained much attention in efforts to develop more sustainable synthetic green chemistry. Each chapter is written by international experts in the field and is a great resource for students, researchers and chemists working in industry to gain an overview on the latest developments.
Author: Arkaitz Correa
Publisher: Springer
ISBN: 3319497847
Category : Science
Languages : en
Pages : 342
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Book Description
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.
Author: Lukiana L. Anka-Lufford
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
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Book Description
"The direct transition-metal catalyzed cross-coupling of two different electrophiles is a fast emerging synthetic method, as it avoids the use of carbon nucleophiles. Despite being a synthetically valuable strategy, a central challenge of cross-electrophile coupling is achieving selectivity for cross-coupled product over dimerization products. This thesis details the author's work towards the development of cross-selective methods for the formation of Csp2-Csp3 bonds. Chapter 1 introduces the conventional cross-coupling method of forming C-C bonds and highlights the advantages of using the reductive cross-electrophile coupling approach instead. The selectivity challenges associated with reductive cross-coupling and the origins of selectivity in the cross-coupling reactions of aryl halides with allylic acetates and benzyl mesylates are discussed. Motivations towards the adaptation of our cross-electrophile coupling methods to more environmentally responsible solvents and reductants are also described. Chapter 2 details a general protocol for the coupling of aryl halides with allylic acetates and shows that high cross-selectivity can be achieved with the use of a terpyridine nickel catalyst. Strength's of the method are presented such tolerance for electrophilic (ketone (71%), aldehyde (70%)) and acidic (sulfonamide (73%), trifluoroacetamide (64%)) substrates and the ability to couple with a variety of substituted allylic acetates. The reductive method addresses the regioselectivity and substrate availability limitations observed in past approaches to allylated arenes. Chapter 3 presents the first synthesis of diarylmethanes from benzyl mesylates and aryl halides using cobalt phthalocyanine (Co(Pc)), a new co-catalyst for radical generation that is compatible with nickel-catalysis. Studies are shown demonstrating the orthogonal reactivity of (dtbbpy)Ni and Co(Pc) and the application of this selectivity to the coupling of functionalized benzyl mesylates with aryl halides. The adaptation of the method to the less reactive benzyl phosphate ester and an enantioconvergent reaction are also presented. Chapter 4 shows studies towards the adaptation of cross-electrophile coupling to more environmentally friendly solvents and reductants. Here, a homogeneous, two electronic organic reductant, 1,2,2-tetrakis(dimethylamino)ethylene (TDAE), is shown to be effective for nickel-catalyzed cross-electrophile coupling in various green solvents such as propylene carbonate and acetonitrile. These reactions are close in yield to our best-reported results in amide or urea solvents using zinc or manganese as the reductant. Chapter 5 describes initial studies towards nickel-catalyzed decarbonylative coupling reactions of acid chloride derivatives with aryl and alkyl halides and nickel-catalyzed coupling reactions of aryl halides with small cyclic alkyl bromides and oxetane tosylate. Further optimization strategies are presented."--Pages viii-ix.
Author: S.L. Buchwald
Publisher: Springer Science & Business Media
ISBN: 3540421750
Category : Medical
Languages : en
Pages : 253
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Book Description
In 1972, a very powerful catalytic cycle for carbon-carbon bond formation was 2 first discovered by the coupling reaction of Grignard reagents at the sp -carbon. Over the past 30 years, the protocol has been substantially improved and expanded to other coupling reactions of Li,B,N,O,Al,Si,P,S,Cu,Mn,Zn,In,Sn, and Hg compounds. These reactions provided an indispensable and simple methodology for preparative organic chemists. Due to the simplicity and rel- bility in the carbon-carbon, carbon-heteroatom, and carbon-metalloid bo- formations,as well as high efficiency of the catalytic process,the reactions have been widely employed by organic chemists in various fields. Application of the protocol ranges from various syntheses of complex natural products to the preparation of biologically relevant molecules including drugs, and of sup- molecules, and to functional materials. The reactions on solid surfaces allow robot synthesis and combinatorial synthesis. Now, many organic chemists do not hesitate to use transition metal complexes for the transformation of org- ic molecules. Indeed, innumerable organic syntheses have been realized by the catalyzed reactions of transition metal complexes that are not achievable by t- ditional synthetic methods. Among these, the metal-catalyzed cross-coupling reactions have undoubtedly contributed greatly to the development of such a new area of “metal-catalyzed organic syntheses”. An excellent monograph for the cross-coupling reactions and other met- catalyzed C-C bond-forming reactions recently appeared in Metal-catalyzed Cross-coupling Reactions (Wiley-VCH,1998).
Author: Rui Shang
Publisher: Springer
ISBN: 9811031932
Category : Science
Languages : en
Pages : 225
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Book Description
This thesis presents the latest developments in new catalytic C–C bond formation methods using easily accessible carboxylate salts through catalytic decarboxylation with good atom economy, and employing the sustainable element iron as the catalyst to directly activate C–H bonds with high step efficiency. In this regard, it explores a mechanistic understanding of the newly discovered decarboxylative couplings and the catalytic reactivity of the iron catalyst with the help of density functional theory calculation. The thesis is divided into two parts, the first of which focuses on the development of a series of previously unexplored, inexpensive carboxylate salts as useful building blocks for the formation of various C–C bonds to access valuable chemicals. In turn, the second part is devoted to several new C–C bond formation methodologies using the most ubiquitous transition metal, iron, as a catalyst, and using the ubiquitous C–H bond as the coupling partner.
Author: Emily Nicole Pinter
Publisher:
ISBN:
Category : Fluorination
Languages : en
Pages : 0
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Book Description
Direct Csp3-H functionalization offers a powerful strategy in organic chemistry that streamlines synthesis and quickly diversifies chemical space. We developed new methods for site-selective Csp3-H functionalization by harnessing nitrogen-based radicals generated from nitrogen-fluorine bonds. Using base metals to homolyze N-F bonds, we create amidyl radicals that undergo intramolecular 1,5-hydrogen atom transfer (HAT). The newly generated alkyl radicals then participate in a variety of coupling reactions to install biologically relevant functional groups. In our first approach, we take advantage of N-fluoroamides for the fluorination of unactivated Csp3-H bonds. The development of this reaction was contingent on identifying the optimal fluoroamide to support Csp3-F bond formation while reducing unwanted by-products. With adamantoyl-derived fluoroamides, high site-selectivity is achieved with mild iron catalysis. Extension of this paradigm to other N-fluoro directing groups was also evaluated and required a meticulous synthetic endeavor. The identity of a viable route to access N-fluorocarbamates allowed us to further evaluate their potential as a directing group for Csp3-H fluorination. Finally, we also developed a copper-catalyzed heteroarylation of Csp3-H bonds using N-fluorosulfonamides. By employing unfunctionalized heterocycles, this method couples two C-H bonds through a cross-dehydrogenative coupling approach, further increasing the reaction efficiency.
Author: Gerhard Erker
Publisher: Springer
ISBN: 3642377599
Category : Science
Languages : en
Pages : 321
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Book Description
Frustrated Lewis Pairs: From Dihydrogen Activation to Asymmetric Catalysis, by Dianjun Chen, Jürgen Klankermayer Coexistence of Lewis Acid and Base Functions: A Generalized View of the Frustrated Lewis Pair Concept with Novel Implications for Reactivity, by Heinz Berke, Yanfeng Jiang, Xianghua Yang, Chunfang Jiang, Subrata Chakraborty, Anne Landwehr New Organoboranes in "Frustrated Lewis Pair" Chemistry, by Zhenpin Lu, Hongyan Ye, Huadong Wang Paracyclophane Derivatives in Frustrated Lewis Pair Chemistry, by Lutz Greb, Jan Paradies Novel Al-Based FLP Systems, by Werner Uhl, Ernst-Ulrich Würthwein N-Heterocyclic Carbenes in FLP Chemistry, by Eugene L. Kolychev, Eileen Theuergarten, Matthias Tamm Carbon-Based Frustrated Lewis Pairs, by Shabana Khan, Manuel Alcarazo Selective C-H Activations Using Frustrated Lewis Pairs. Applications in Organic Synthesis, by Paul Knochel, Konstantin Karaghiosoff, Sophia Manolikakes FLP-Mediated Activations and Reductions of CO2 and CO, by Andrew E. Ashley, Dermot O’Hare Radical Frustrated Lewis Pairs, by Timothy H. Warren and Gerhard Erker Polymerization by Classical and Frustrated Lewis Pairs, by Eugene Y.-X. Chen Frustrated Lewis Pairs Beyond the Main Group: Transition Metal-Containing Systems, by D. Wass Reactions of Phosphine-Boranes and Related Frustrated Lewis Pairs with Transition Metal Complexes, by Abderrahmane Amgoune, Ghenwa Bouhadir, Didier Bourissou
Author: Marc Taillefer
Publisher: Springer
ISBN: 9783662505663
Category : Science
Languages : en
Pages : 0
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Book Description
Palladium-Catalyzed sp2C–N Bond Forming Reactions: Recent Developments and Applications. Metal-catalyzed C(sp2)-N bond formation.- Recent Developments in Recyclable Copper Catalyst Systems for C−N Bond Forming Cross-Coupling Reactions Using Aryl Halides and Arylboronic Acids. Assembly of N-containing heterocycles via Pd and Cu-catalyzed C-N bond formation reactions. Copper-Catalyzed C(aryl)-N Bond Formation.
