[PDF] Palladium Catalyzed Synthesis Of Functionalized Heterocycles eBook

Author : Imran Malik
Publisher : LAP Lambert Academic Publishing
Page : 140 pages
File Size : 37,10 MB
Release : 2011-09
Category :
ISBN : 9783846503188

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Transition metals (Pd, Ni, Cu, Fe, Au) have played significant role in organic chemistry for creating organic molecules. One metal palladium with different ligands is being used as efficient catalyst for C-C bond formation. Palladium catalyzed reactions are used in the synthesis of many natural products, pharmaceutical drugs and advance materials. In this research work, Heck, Suzuki and Sonogashira reactions of di and tri halogenated and dihydroxy heterocycles (benzothiophene, pyrazine, quinoxaline, pyrimidine, furan and flavone) with photophysical properties of some alkynylated products of Pyrimidines and furans, have been studied in detail.

Author : Alena Rudolph
Publisher :
Page : 802 pages
File Size : 11,86 MB
Release : 2009
Category :
ISBN : 9780494525395

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Our group has expanded the synthetic utility of a palladium-catalyzed norbornene-mediated domino process first described by Catellani, to access a variety of fused aromatic heterocycles and medicinally relevant scaffolds.Chapter 1 describes a domino aromatic alkylation/Heck reaction sequence to generate tricyclic heterocycles. We significantly expanded the scope of this reaction to include a variety of heteroatoms including sulphur, nitrogen, benzylic oxygens and silicon. In particular, tricyclic analogues of mescaline, implicated in the treatment of disorders such as schizophrenia and depression, are easily accessed by this method.Chapter 2 examines the application of unactivated secondary alkyl halides as the aromatic alkylating reagent in this process. We have successfully demonstrated that secondary alkyl halides react intramolecularly and intermolecularly, and stereospecifically to afford a variety of polycyclic heterocycles. A number of termination steps have also proved to be compatible with this process, such as the Heck reaction, the direct arylation of heterocycles and a Buchwald-Hartwig amination. Notably, we used the structural features of these secondary alkyl halides to gain key stereochemical and mechanistic information for the overall palladium-catalyzed reaction.Chapter 3 describes a second area of research within our group that investigates the development of desymmetrizing ring-opening reactions via the addition of nucleophiles to strained meso bicyclic alkenes to afford tetrahydronaphthalene cores. Specifically the palladium-catalyzed, asymmetric ring opening of azabenzonorbornadiene with organoborons is investigated, which proceeds with moderate to good enantioselectivities depending on the nature of the boronic acid employed. Others in our group have recently demonstrated the utility of this methodology in the first asymmetric syntheses of a family of naturally occurring alkaloids, displaying a wide variety of pharmacological activities.

Author : Xiao-Feng Wu
Publisher : Royal Society of Chemistry
Page : 315 pages
File Size : 44,4 MB
Release : 2015
Category : Science
ISBN : 1782621369

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An introduction to transition metal catalyzed coupling reactions of double-functionalized arenes in heterocycle synthesis.

Author : Xiaojun Han
Publisher :
Page : 644 pages
File Size : 36,87 MB
Release : 1998
Category :
ISBN :

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Palladium catalyzes the regio- and stereoselective annulation of allenes by vinylic halides bearing tertiary alcohol and p-toluenesulfonamide groups to produce a variety of 5- and 6-membered ring heterocycles containing a 1,3-diene moiety. In addition, the palladium-catalyzed reaction of N-(2-iodo-2-alkenyl)--P-toluenesulfonamides with diphenylacetylene or 4,4-dimethyl-2-pentyne affords pyrolidine derivatives containing a 1,3-diene moiety, or unexpected 2-alkenyl substituted [Alpha, Beta-]unsaturated aldehydes. These synthetically useful intermediates are difficult to prepare or inaccessible by other existing methodology. A number of 3,4,6-tri- and 3,4,5,6-tetrasubstituted [Alpha]-pyrones have been prepared in good yields by the reaction of vinylic iodides or triflates bearing ester functionality with internal alkynes in the presence of a palladium catalyst. The methodology provides an especially simple, convenient, and regioselective route to [Alpha]-pyrones containing aryl, silyl, tert.-alkyl and other hindered groups.

Author : Hyung Yoon
Publisher : Springer Nature
Page : 236 pages
File Size : 39,11 MB
Release : 2020-09-02
Category : Science
ISBN : 3030540774

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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.

Author : Shinsuke Inuki
Publisher : Springer Science & Business Media
Page : 115 pages
File Size : 14,45 MB
Release : 2011-11-23
Category : Science
ISBN : 4431540431

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The author has developed novel methodologies for highly efficient construction of functionalized heterocycles by palladium-catalyzed domino/cascade cyclization of allenes and related compounds containing appropriate nucleophilic group(s). Based on these methodologies, enantioselective total syntheses of bioactive natural products, pachastrissamine (26% overall yield in seven steps), lysergic acid (4.0% overall yield in fifteen steps), lysergol (3.6% overall yield in fifteen steps) and isolysergol (8.2% overall yield in eleven steps) have been achieved. These are more facile synthetic route than those previously reported. These findings would contribute to the development of efficient synthetic methods for biologically active compounds containing a complex structure.

Author : Navjeet Kaur
Publisher : CRC Press
Page : 482 pages
File Size : 49,98 MB
Release : 2019-05-01
Category : Medical
ISBN : 1351242598

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This book is a compilation of the recent applications of palladium catalysts in organic synthesis. The book demonstrates that it is a highly dynamic research field. This methodology has emerged as a powerful tool for the efficient and chemoselective synthesis of heterocyclic molecules. In the past few years, several strategies have been pointed out to pursue more efficient, sustainable, and environment friendly chemical processes. Among those strategies, catalysis and the design of new processes that avoid the use of toxic reagents have been the focus of intense research.

Author : Marco Bandini
Publisher : Springer
Page : 294 pages
File Size : 44,33 MB
Release : 2016-07-01
Category : Science
ISBN : 3319351443

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The series Topics in Heterocyclic Chemistry presents critical reviews on present and future trends in the research of heterocyclic compounds. Overall the scope is to cover topics dealing with all areas within heterocyclic chemistry, both experimental and theoretical, of interest to the general heterocyclic chemistry community. The series consists of topic related volumes edited by renowned editors with contributions of experts in the field. All chapters from Topics in Heterocyclic Chemistry are published Online First with an individual DOI. In references, Topics in Heterocyclic Chemistry is abbreviated as Top Heterocycl Chem and cited as a journal

Author : Dino Alberico
Publisher :
Page : 748 pages
File Size : 41,3 MB
Release : 2006
Category :
ISBN : 9780494157459

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Chapter 2 examines a sequence in which two alkyl-aryl bonds and one alkenyl/aryl bond are formed in one pot. The reaction conditions were optimized and the scope was examined. A variety of symmetrical and unsymmetrical tricyclic heterocycles were synthesized in good yields from a Heck acceptor and an aryl iodide containing two tethered alkyl bromides. This methodology was applied to the synthesis of a tricyclic mescaline analogue. We have developed a norbornene-mediated palladium-catalyzed tandem reaction for the preparation of fused aromatic carbocycles and heterocycles. Chapter 1 describes an alkylation/alkenylation sequence using aryl iodides and bromoenoates. The effect of substitution on the bromoenoate was evaluated. A wide variety of carbon-, oxygen-, and nitrogen-containing functional groups are tolerated allowing for rapid access to highly functionalized aromatic carbocycles. Chapter 3 describes an alkylation/C-H functionalization sequence. In this highly efficient approach, an alkyl-aryl bond and an aryl-heteroaryl bond are created from two C-H bonds in a one-pot process. A wide range of functionalized annulated indoles were synthesized in a convergent manner in high yields.