The Development of Palladium- and Copper-catalyzed Transformations for the Asymmetric Synthesis of Biologically Active Small Molecules

The Development of Palladium- and Copper-catalyzed Transformations for the Asymmetric Synthesis of Biologically Active Small Molecules
Author: James Thomas Masters
Publisher:
Total Pages:
Release: 2016
Genre:
ISBN:

Download The Development of Palladium- and Copper-catalyzed Transformations for the Asymmetric Synthesis of Biologically Active Small Molecules Book in PDF, Epub and Kindle

The continued demand for efficient chemo-, regio-, and stereoselective organic transformations motivates the development of new chemical reactions. Transition metal catalysis represents a powerful method for the construction of carbon-carbon, carbon-hydrogen, and carbon-heteroatom bonds in a highly selective fashion. This dissertation describes the development of several new transition metal-catalyzed organic reactions useful in the preparation of various chiral small molecules, including both fundamental organic "building block" compounds and structurally complex natural products and pharmaceutical agents. We report a new strategy for the synthesis of chiral beta-alkynyl esters, ketones, and sulfones via sequential palladium-catalyzed carbon-carbon bond formation and copper-catalyzed carbon-hydrogen bond formation. The process is operationally straightforward, compatible with a broad range of substrates, and delivers the targets in high yields with excellent levels of enantioselectivity. It is compatible with both oxygen and nitrogen functionality, and this enabled the rapid elaboration of the products into a diverse set of chiral heterocycles. The sequential catalysis protocol was employed in a concise, enantioselective synthesis of AMG 837, a potent agonist of G-protein coupled receptor 40. Recognizing both the biological relevance of chiral alkaloids and the synthetic challenges associated with the construction of quaternary, all-carbon stereocenters, we pursued a palladium-catalyzed asymmetric allylic alkylation that effected carbon-carbon bond formation on prochiral oxindole nucleophiles. Although prior research has demonstrated that allylic alkylation reactions of geminal dicarboxylate electrophiles typically yield branched products as the result of ipso-addition, we identify conditions wherein oxindoles react with a dipivaloyl electrophile to afford linear enol pivalate compounds. A mild hydrolysis reaction converts these products into the aldehyde that formally results from asymmetric conjugate addition to acrolein, a challenging transformation with limited literature precedent. These adducts are established precursors to tricyclic alkaloid scaffolds of pharmaceutical interest. Chiral gamma-heteroatom-substituted cycloalkenones are well-established organic "building blocks" that are widely used in the synthesis of complex molecules. The exposure of meso-1,4-allylic dibenzoates to chiral phosphine-ligated palladium salts in the presence of a potassium nitronate nucleophile promotes a unique oxidative desymmetrization reaction. This process yields enantiopure gamma-benzoyloxy cyclopentenones, cyclohexenones, and cycloheptenones. We describe the elaboration of these products into diverse, enantioenriched oxygen- and nitrogen-substituted cycloalkenones via subsequent palladium-catalyzed allylic alkylation reactions involving heteroatom nucleophiles. Separately, we employ enantiopure gamma-benzoyloxy cyclohexenones in short, asymmetric syntheses of enantio- and diastereomerically diverse epoxyquinoid natural products. We further highlight the utility of palladium catalysis in complex molecule synthesis through the development of a unique, intramolecular carbon-carbon bond-forming reaction that generates a strained enyne and through an asymmetric formal synthesis of aliskiren, a renin inhibitor used in the treatment of hypertension.

Asymmetric Metal Catalysis in Enantioselective Domino Reactions

Asymmetric Metal Catalysis in Enantioselective Domino Reactions
Author: Helene Pellissier
Publisher: John Wiley & Sons
Total Pages: 342
Release: 2019-07-12
Genre: Science
ISBN: 3527822526

Download Asymmetric Metal Catalysis in Enantioselective Domino Reactions Book in PDF, Epub and Kindle

Introduces an innovative and outstanding tool for the easy synthesis of complex chiral structures in a single step Covering all of the literature since the beginning of 2006, this must-have book for chemists collects the major progress in the field of enantioselective one-, two-, and multicomponent domino reactions promoted by chiral metal catalysts. It clearly illustrates how enantioselective metal-catalyzed processes constitute outstanding tools for the development of a wide variety of fascinating one-pot asymmetric domino reactions, thereby allowing many complex products to be easily generated from simple materials in one step. The book also strictly follows the definition of domino reactions by Tietze as single-, two-, as well as multicomponent transformations. Asymmetric Metal Catalysis in Enantioselective Domino Reactions is divided into twelve chapters, dealing with enantioselective copper-, palladium-, rhodium-, scandium-, silver-, nickel-, gold-, magnesium-, cobalt-, zinc-, yttrium and ytterbium-, and other metal-catalyzed domino reactions. Most of the chapters are divided into two parts dealing successively with one- and two-component domino reactions, and three-component processes. Each part is subdivided according to the nature of domino reactions. Each chapter of the book includes selected applications of synthetic methodologies to prepare natural and biologically active products. -Presents the novel combination of asymmetric metal catalysis with the concept of fascinating domino reactions, which allows high molecular complexity with a remarkable level of enantioselectivity -Showcases an incredible tool synthesizing complex and diverse chiral structures in a single reaction step -Includes applications in total synthesis of natural products and biologically active compounds -Written by a renowned international specialist in the field -Stimulates the design of novel asymmetric domino reactions and their use in the synthesis of natural products, pharmaceuticals, agrochemicals, and materials Asymmetric Metal Catalysis in Enantioselective Domino Reactions will be of high interest to synthetic, organic, medicinal, and catalytic chemists in academia and R&D departments.

Copper Catalysis in Organic Synthesis

Copper Catalysis in Organic Synthesis
Author: Gopinathan Anilkumar
Publisher: John Wiley & Sons
Total Pages: 504
Release: 2020-07-08
Genre: Technology & Engineering
ISBN: 3527826432

Download Copper Catalysis in Organic Synthesis Book in PDF, Epub and Kindle

The most current information on growing field of copper catalysis Copper Catalysis in Organic Synthesis contains an up-to-date overview of the most important reactions in the presence of copper catalysts. The contributors—noted experts on the topic—provide an introduction to the field of copper catalysis, reviewing its development, scope, and limitations, as well as providing descriptions of various homo- and cross-coupling reactions. In addition, information is presented on copper-catalyzed C–H activation, amination, carbonylation, trifluoromethylation, cyanation, and click reactions. Comprehensive in scope, the book also describes microwave-assisted and multi-component transformations as well as copper-catalyzed reactions in green solvents and continuous flow reactors. The authors highlight the application of copper catalysis in asymmetric synthesis and total synthesis of natural products and heterocycles as well as nanocatalysis. This important book: Examines copper and its use in organic synthesis as a more cost-effective and sustainable for researchers in academia and industry Offers the first up-to-date book to explore copper as a first line catalyst for many organic reactions Presents the most significant developments in the area, including cross-coupling reactions, C–H activation, asymmetric synthesis, and total synthesis of natural products and heterocycles Contains over 20 contributions from leaders in the field Written for catalytic chemists, organic chemists, natural products chemists, pharmaceutical chemists, and chemists in industry, Copper Catalysis in Organic Synthesis offers a book on the growing field of copper catalysis, covering cross-coupling reactions, C–H activation, and applications in the total synthesis of natural products.

Palladium and Nickel Catalyzed Transformations Forming Functionalized Heterocycles

Palladium and Nickel Catalyzed Transformations Forming Functionalized Heterocycles
Author: Hyung Yoon
Publisher: Springer Nature
Total Pages: 236
Release: 2020-09-02
Genre: Science
ISBN: 3030540774

Download Palladium and Nickel Catalyzed Transformations Forming Functionalized Heterocycles Book in PDF, Epub and Kindle

This book presents Pd- and Ni-catalyzed transformations generating functionalized heterocycles. Transition metal catalysis is at the forefront of synthetic organic chemistry since it offers new and powerful methods to forge carbon–carbon bonds in high atom- and step-economy. In Chapter 1, the author describes a Pd- and Ni-catalyzed cycloisomerization of aryl iodides to alkyl iodides, known as carboiodination. In the context of the Pd-catalyzed variant, the chapter explores the production of enantioenriched carboxamides through diastereoselective Pd-catalyzed carboiodination. It then discusses Ni-catalyzed reactions to generate oxindoles and an enantioselective variant employing a dual ligand system. Chapter 2 introduces readers to a Pd-catalyzed diastereoselective anion-capture cascade. It also examines diastereoselective Pd-catalyzed aryl cyanation to synthesize alkyl nitriles, a method that generates high yields of borylated chromans as a single diastereomer, and highlights its synthetic utility. Lastly, Chapter 3 presents a Pd-catalyzed domino process harnessing carbopalladation, C–H activation and π-system insertion (benzynes and alkynes) to generate spirocycles. It also describes the mechanistic studies performed on these reactions.

The Development of Palladium-, Zinc-, and Magnesium-catalyzed Asymmetric Transformations

The Development of Palladium-, Zinc-, and Magnesium-catalyzed Asymmetric Transformations
Author: Sushant Malhotra
Publisher:
Total Pages:
Release: 2010
Genre:
ISBN:

Download The Development of Palladium-, Zinc-, and Magnesium-catalyzed Asymmetric Transformations Book in PDF, Epub and Kindle

Natural products have laid the foundation for the discovery and development of medicines for centuries. Early Ayurvedic medicine involved the use of cocktails of several naturally occurring molecules for the treatment of common illnesses. Today natural products remain the mainstay of therapeutic intervention in the treatment of several debilitating diseases. Compounds accessed from natural sources have also been the source of inspiration in the discovery of several non-natural pharmaceuticals. The diverse and complex structural features of natural products and their limited availability, however, presents a significant roadblock in accessing these molecules on scales where they can have the greatest impact. Currently, the de novo synthesis of natural products is challenging, expensive, and low yielding. To address this, chemists strive to access structures with the greatest efficiency and practicality. Despite decades of efforts we are still faced with the challenge of synthetic efficiency. Herein, the cytotoxic agent Peloruside A, the antibiotic tobramycin, the multi-drug resistance reversal agent N-acetyl-ardeemin have inspired the discovery and development of methods to streamline the synthesis of these molecules and their analogs. Detailed is an account of the efforts dedicated towards accessing these natural products in high efficiency and in enantiomerically enriched form using novel disconnections which have led to the development of several new methods. Peloruside A has inspired the development of the asymmetric desymmetrization of 2-alkyl-1,3-propanediols. This method was found to be highly general and rapidly afforded several chiral building blocks. One of these is applied towards the synthesis of an important fragment in this natural product. Peloruside A also highlighted the deficiencies in using esters in direct asymmetric aldol reactions. The development of a diazoester aldol using of commercially available ethyl diazoacetate and a range of aldehydes is a viable alternative to the use of chiral pool-based auxiliaries. To minimize the use of protecting groups the use of an alkyne as a masked [Alpha]-hydroxyketone has been explored in the formation of the pyran ring in peloruside A via a 6-endo-dig cyclization. The development of the asymmetric diazoester aldol reaction led to the synthesis of vicinal diols bearing a tertiary alcohol. The oxidation of [Beta]-hydroxy-[Alpha]-diazoesters affords [Beta]-hydroxy-[Alpha]-ketoesters that undergo alkyl transfer with minimal erosion in chirality and in high diastereocontrol with alkyl, allyl, and propargyl nucleophiles. One of the products from this method is present in azithromycin and related natural products. Furthermore, the asymmetric diazoester aldol reaction enables the exploration of a direct stereospecific C--O to C--N exchange reaction unique to diazoesters towards the synthesis of [Beta]-amido-[Alpha]-diazoesters. The products from this reaction can be transformed into [Beta]-amido-[Alpha]-hydroxyesters and undergo a rather unusual 1,3-C--H insertion reaction to afford aminocyclopropanes. The use of nitrogen nucleophiles in Pd-catalyzed asymmetric allylic alkylations enabled the synthesis of two diastereoisomers of 2-deoxystreptamine. This motif is present in all clinically relevant aminoglycoside antibiotics; however, the biological effects of aminoglycosides that are diastereomeric at the 2-deoxystreptamine core are unexplored. A synthetic sequence that furnishes scaffolds that have the potential of being transformed into novel aminoglycosides is presented. This project highlighted the challenge of generating diamines. Recognizing this, a collaboration with the Du Bois group at Stanford University was initiated where the use of a bifunctional nucleophile in sequential palladium- and rhodium-catalyzed processes afforded several nitrogenated architectures that cannot be readily accessed by pre-existing methods and can serve as building blocks in drug discovery. One interesting facet of this work was the use of [Pi]-prenylpalladium species in directing attack of a nitrogen nucleophile at the more substituted carbon of a prenyl electrophile. The reverse prenylated hexahydropyrrolo[2,3-b]indoline substructure is present in several natural products such as N-acetyl-ardeemin. One reason for the challenge associated in employing [Pi]-prenylpalladium complexes to access these natural products lies in the concomitant control of the regio- and enantioselectivity with sterically more demanding carbon based nucleophiles. Although usually Pd-catalyzed allylic alkylations result in attack at the less hindered terminus of a [Pi]-allyl, described are conditions where the regioselectivity can be controlled in accessing either linear or branched prenylated products in high optical purities. In one example the enantio-, regio- and diastereoselective synthesis of vicinal quaternary stereogenic centers has been achieved using palladium catalyzed allylic alkylations.

Copper-Catalyzed Multi-Component Reactions

Copper-Catalyzed Multi-Component Reactions
Author: Yusuke Ohta
Publisher: Springer Science & Business Media
Total Pages: 110
Release: 2011-01-20
Genre: Science
ISBN: 3642154735

Download Copper-Catalyzed Multi-Component Reactions Book in PDF, Epub and Kindle

A copper-catalyzed direct synthesis of 2-(aminomethyl)indoles by catalytic domino reaction including multi-component coupling was developed, and is the first example of a three-component indole formation without producing salts as a byproduct. Based on this reaction, a copper-catalyzed synthesis of 3-(aminomethyl)isoquinoline was accomplished which represents an unprecedented isoquinoline synthesis through a four-component coupling reaction. Following these results, extensive application studies using one-pot palladium-, acid-, or base-promoted cyclization revealed that indole- or isoquinoline-fused polycyclic compounds can be readily synthesized through multi-component reactions. As the concept of Green Chemistry becomes ever more important, these findings may provide efficient and atom-economical approaches to the diversity-oriented synthesis of bioactive compounds containing a complex structure. This could lead to development of promising drug leads with structural complexity. The work of this thesis will go on to inspire the synthetic research of many readers.

Applications of Transition Metal Catalysis in Drug Discovery and Development

Applications of Transition Metal Catalysis in Drug Discovery and Development
Author: Matthew L. Crawley
Publisher: John Wiley & Sons
Total Pages: 386
Release: 2012-07-03
Genre: Science
ISBN: 0470631325

Download Applications of Transition Metal Catalysis in Drug Discovery and Development Book in PDF, Epub and Kindle

This book focuses on the drug discovery and development applications of transition metal catalyzed processes, which can efficiently create preclinical and clinical drug candidates as well as marketed drugs. The authors pay particular attention to the challenges of transitioning academically-developed reactions into scalable industrial processes. Additionally, the book lays the groundwork for how continued development of transition metal catalyzed processes can deliver new drug candidates. This work provides a unique perspective on the applications of transition metal catalysis in drug discovery and development – it is a guide, a historical prospective, a practical compendium, and a source of future direction for the field.

Palladium-catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals

Palladium-catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals
Author: Yiyang Liu
Publisher:
Total Pages: 1012
Release: 2015
Genre: Electronic dissertations
ISBN:

Download Palladium-catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals Book in PDF, Epub and Kindle

Decarboxylation and decarbonylation are important reactions in synthetic organic chemistry, transforming readily available carboxylic acids and their derivatives into various products through loss of carbon dioxide or carbon monoxide. In the past few decades, palladium-catalyzed decarboxylative and decarbonylative reactions experienced tremendous growth due to the excellent catalytic activity of palladium. Development of new reactions in this category for fine and commodity chemical synthesis continues to draw attention from the chemistry community. The Stoltz laboratory has established a palladium-catalyzed enantioselective decarboxylative allylic alkylation of beta-keto esters for the synthesis of alpha-quaternary ketones since 2005. Recently, we extended this chemistry to lactams due to the ubiquity and importance of nitrogen-containing heterocycles. A wide variety of alpha-quaternary and tetrasubstituted alpha-tertiary lactams were obtained in excellent yields and exceptional enantioselectivities using our palladium-catalyzed decarboxylative allylic alkylation chemistry. Enantioenriched alpha-quaternary carbonyl compounds are versatile building blocks that can be further elaborated to intercept synthetic intermediates en route to many classical natural products. Thus our chemistry enables catalytic asymmetric formal synthesis of these complex molecules. In addition to fine chemicals, we became interested in commodity chemical synthesis using renewable feedstocks. In collaboration with the Grubbs group, we developed a palladium-catalyzed decarbonylative dehydration reaction that converts abundant and inexpensive fatty acids into value-added linear alpha olefins. The chemistry proceeds under relatively mild conditions, requires very low catalyst loading, tolerates a variety of functional groups, and is easily performed on a large scale. An additional advantage of this chemistry is that it provides access to expensive odd-numbered alpha olefins. Finally, combining features of both projects, we applied a small-scale decarbonylative dehydration reaction to the synthesis of alpha-vinyl carbonyl compounds. Direct alpha-vinylation is challenging, and asymmetric vinylations are rare. Taking advantage of our decarbonylative dehydration chemistry, we were able to transform enantioenriched delta-oxocarboxylic acids into quaternary alpha-vinyl carbonyl compounds in good yields with complete retention of stereochemistry. Our explorations culminated in the catalytic enantioselective total synthesis of (-)-aspewentin B, a terpenoid natural product featuring a quaternary alpha-vinyl ketone. Both decarboxylative and decarbonylative chemistries found application in the late stage of the total synthesis.

Copper-Catalyzed Multi-Component Reactions

Copper-Catalyzed Multi-Component Reactions
Author: Yusuke Ohta
Publisher: Springer
Total Pages: 120
Release: 2011-03-30
Genre:
ISBN: 9783642154744

Download Copper-Catalyzed Multi-Component Reactions Book in PDF, Epub and Kindle

As the concept of Green Chemistry becomes ever more important, the findings presented in this book may provide efficient and atom-economical approaches to the diversity-oriented synthesis of bioactive compounds containing a complex structure.