scholarly journals Formal Electrophilic Phenylation Reaction with Tropylium Ion

2021 ◽  
Author(s):  
Demelza Lyons ◽  
An Huy Dinh ◽  
Reece Crocker ◽  
Binh Khanh Mai ◽  
Thanh Vinh Nguyen
Keyword(s):  
Reactive Intermediates ◽  
Building Blocks ◽  
Synthetic Chemistry ◽  
Coupling Reactions ◽  
Ring Contraction ◽  
Aryl Radicals ◽  
Biaryl Coupling ◽  
New Strategy

Arylation reaction is an important transformation in synthetic chemistry as aryl building blocks are ubiquitous in valuable organic frameworks. Traditionally, this type of reaction has been carried out either via biaryl coupling reactions or with the use of reactive intermediates such as arynes or aryl radicals. Direct electrophilic arylation reactions have been rarely reported in literature, as the required arenium building blocks are often unstable or inaccessible. To develop a new strategy for such transformation, we herein introduce the development of a formal phenylation reaction, which proceeds via an electrophilic cycloheptatrienylation with tropylium ion, followed by an oxidative ring-contraction.

scholarly journals Formal Electrophilic Phenylation Reaction with Tropylium Ion

2021 ◽  
Author(s):  
Demelza Lyons ◽  
An Huy Dinh ◽  
Reece Crocker ◽  
Binh Khanh Mai ◽  
Thanh Vinh Nguyen
Keyword(s):  
Reactive Intermediates ◽  
Building Blocks ◽  
Synthetic Chemistry ◽  
Coupling Reactions ◽  
Ring Contraction ◽  
Aryl Radicals ◽  
Biaryl Coupling ◽  
New Strategy

Arylation reaction is an important transformation in synthetic chemistry as aryl building blocks are ubiquitous in valuable organic frameworks. Traditionally, this type of reaction has been carried out either via biaryl coupling reactions or with the use of reactive intermediates such as arynes or aryl radicals. Direct electrophilic arylation reactions have been rarely reported in literature, as the required arenium building blocks are often unstable or inaccessible. To develop a new strategy for such transformation, we herein introduce the development of a formal phenylation reaction, which proceeds via an electrophilic cycloheptatrienylation with tropylium ion, followed by an oxidative ring-contraction.

New Perspectives for Iodine (III) Reagents in (Hetero)Biaryl Coupling Reactions

2002 ◽  
Vol 6 (15) ◽  
pp. 1433-1452 ◽  
Author(s):  
I. Moreno ◽  
I. Tellitu ◽  
M. Herrero ◽  
R. SanMartin ◽  
E. Dominguez
Keyword(s):  
Coupling Reactions ◽  
Biaryl Coupling

Catch It If You Can: Copper-Catalyzed (Transfer) Hydrogenation Reactions and Coupling Reactions by Intercepting Reactive Intermediates Thereof

Synthesis ◽  
2020 ◽  
Vol 52 (17) ◽  
pp. 2483-2496
Author(s):  
Johannes F. Teichert ◽  
Lea T. Brechmann
Keyword(s):  
Coupling Reaction ◽  
Reactive Intermediates ◽  
Transfer Hydrogenation ◽  
Coupling Reactions ◽  
Bond Forming ◽  
Starting Point ◽  
Bond Forming Reactions ◽  
Hydrogenation Reactions ◽  
Multicomponent Coupling Reactions ◽  
Trapping Reactions

The key reactive intermediate of copper(I)-catalyzed alkyne semihydrogenations is a vinylcopper(I) complex. This intermediate can be exploited as a starting point for a variety of trapping reactions. In this manner, an alkyne semihydrogenation can be turned into a dihydrogen­-mediated coupling reaction. Therefore, the development of copper-catalyzed (transfer) hydrogenation reactions is closely intertwined with the corresponding reductive trapping reactions. This short review highlights and conceptualizes the results in this area so far, with H2-mediated carbon–carbon and carbon–heteroatom bond-forming reactions emerging under both a transfer hydrogenation setting as well as with the direct use of H2. In all cases, highly selective catalysts are required that give rise to atom-economic multicomponent coupling reactions with rapidly rising molecular complexity. The coupling reactions are put into perspective by presenting the corresponding (transfer) hydrogenation processes first.1 Introduction: H2-Mediated C–C Bond-Forming Reactions2 Accessing Copper(I) Hydride Complexes as Key Reagents for Coupling Reactions; Requirements for Successful Trapping Reactions 3 Homogeneous Copper-Catalyzed Transfer Hydrogenations4 Trapping of Reactive Intermediates of Alkyne Transfer Semi­hydrogenation Reactions: First Steps Towards Hydrogenative Alkyne Functionalizations 5 Copper(I)-Catalyzed Alkyne Semihydrogenations6 Copper(I)-Catalyzed H2-Mediated Alkyne Functionalizations; Trapping of Reactive Intermediates from Catalytic Hydrogenations6.1 A Detour: Copper(I)-Catalyzed Allylic Reductions, Catalytic Generation of Hydride Nucleophiles from H2 6.2 Trapping with Allylic Electrophiles: A Copper(I)-Catalyzed Hydro­allylation Reaction of Alkynes 6.3 Trapping with Aryl Iodides7 Conclusion

A New Strategy for Solid-Phase Depsipeptide Synthesis Using Recoverable Building Blocks

2005 ◽  
Vol 7 (4) ◽  
pp. 597-600 ◽  
Author(s):  
Fernando Albericio ◽  
Klaus Burger ◽  
Javier Ruíz-Rodríguez ◽  
Jan Spengler
Keyword(s):  
Solid Phase ◽  
Building Blocks ◽  
New Strategy

Heterogeneous Metal Catalysis for the Environmentally Benign Synthesis of Medicinally Important Scaffolds, Intermediates, and Building Blocks

2021 ◽  
Vol 25 ◽  
Author(s):  
Maysa Ilamanova ◽  
Maxim Mastyugin ◽  
Christian Schäfer ◽  
Anne Kokel ◽  
Béla Török
Keyword(s):  
Building Blocks ◽  
Metal Catalysts ◽  
Solid Metal ◽  
Coupling Reactions ◽  
Hydrogenation Catalysts ◽  
Metal Catalysis ◽  
Solid Catalysts ◽  
Cross Coupling Reactions ◽  
Benign Synthesis ◽  
Two Sides

: This account provides a broad overview of the application of solid metal catalysts in synthetic chemistry with a focus on the synthesis of medicinally important scaffolds or building blocks. Heterogeneous catalysis is a fundamental contributor to green or sustainable synthesis. Despite this, many synthetic chemists overwhelmingly focus on homogeneous methods, and due to their unfamiliarity with solid catalysts, many would not consider using them. The primary purpose of this work is to bring solid catalysts and their application possibilities to the attention of synthetic chemists in a format that focuses on reactions, thus building a bridge between the two sides for the benefit of sustainable applications and, eventually, the whole society. The two major parts of this account describe the common types of solid metal catalysts and the applications of these catalysts in sustainable synthesis. The first part gives an overview of the major types of solid metal catalysts, including common hydrogenation catalysts to metal nanoparticles. The second and more extensive part illustrates the use of these catalysts in a thematic order based on reaction types, including hydrogenation, hydrogenolysis, oxidation, metathesis, cross-coupling reactions, and hydroformylation.

scholarly journals Harnessing Chemical Energy for the Activation and Joining of Prebiotic Building Blocks

2019 ◽  
Author(s):  
Ziwei Liu ◽  
Long-Fei Wu ◽  
Jianfeng Xu ◽  
Claudia Bonfio ◽  
David Russell ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Carboxylic Acid ◽  
Peptide Nucleic Acid ◽  
Reactive Intermediates ◽  
Building Blocks ◽  
Acid System ◽  
Rna Oligomers ◽  
Prebiotic Activation ◽  
Simultaneous Activation ◽  
Acid Anhydrides

Simultaneous activation of carboxylates and phosphates provides multiple pathways for the generation of reactive intermediates, including mixed carboxylic acid-phosphoric acid anhydrides, for the synthesis of peptidyl-RNAs, peptides, RNA oligomers and primordial phospholipids. These results indicate that unified prebiotic activation chemistry could have enabled the joining of building blocks in aqueous solution from a common pool and enabled the progression of a system towards higher complexity foreshadowing the modern encapsulated peptide-nucleic acid system

ChemInform Abstract: Highly Chemoselective Cobalt-Catalyzed Biaryl Coupling Reactions.

ChemInform ◽  
2013 ◽  
Vol 44 (27) ◽  
pp. no-no
Author(s):  
Samet Guelak ◽  
Ondrej Stepanek ◽  
Jennifer Malberg ◽  
Babak Rezaei Rad ◽  
Martin Kotora ◽  
...  
Keyword(s):  
Coupling Reactions ◽  
Biaryl Coupling

Enantioselective Intermolecular Murai-Type Alkene Hydroarylation Reactions

Synthesis ◽  
2021 ◽  
Author(s):  
John F. Bower ◽  
Timothy P. Aldhous ◽  
Raymond W. M. Chung ◽  
Andrew G. Dalling
Keyword(s):  
Building Blocks ◽  
Short Review ◽  
Synthetic Chemistry ◽  
Complex Building

AbstractStrategies that enable the efficient assembly of complex building blocks from feedstock chemicals are of paramount importance to synthetic chemistry. Building upon the pioneering work of Murai and co-workers in 1993, C–H-activation-based enantioselective hydroarylations of alkenes offer a particularly promising framework for the step- and atom-economical installation of benzylic stereocenters. This short review presents recent intermolecular enantioselective Murai-type alkene hydroarylation methodologies and the mechanisms by which they proceed.1 Introduction2 Enantioselective Hydroarylation Reactions of Strained Bicyclic Alkenes3 Enantioselective Hydroarylation Reactions of Electron-Rich Acyclic Alkenes4 Enantioselective Hydroarylation Reactions of Electron-Poor Acyclic Alkenes5 Enantioselective Hydroarylation Reactions of Minimally Polarized Acyclic Alkenes6 Conclusion and Outlook

[4+n] Annulation Reactions Using ortho-Halomethyl Anilines as Aza-ortho-Quinone Methide Precursors

Synthesis ◽  
2021 ◽  
Author(s):  
Xiao-Yu He ◽  
Yu-Hong Ma ◽  
Qing-Qing Yang ◽  
Wen-Jing Xiao
Keyword(s):  
Convenient Method ◽  
Reactive Intermediates ◽  
Quinone Methide ◽  
Synthetic Chemistry ◽  
Important Class ◽  
Quinone Methides ◽  
Aniline Derivatives

Aza-ortho-quinone methides are an important class of reactive intermediates, which have found broad applications in synthetic chemistry. Recently, 1,4-elimination of ortho-halomethyl aniline derivatives has emerged as a new powerful and convenient method for aza-ortho-quinone methide generation. This review will highlight their recent applications as aza-ortho-quinone methide precursors in annulation reactions to access various biologically important nitrogen-containing heterocycles. The general mechanisms are briefly discussed as well.

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