Copper and Palladium Catalyzed Benz-fused Heterocycle Synthesis Via Intramolecular Cross-Coupling and C---H Bond Functionalization Strategies PDF Download
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Author: Laurie Lynn Joyce Publisher: ISBN: Category : Languages : en Pages : 906
Book Description
This thesis is a summary of research conducted in the laboratory of Professor Robert A. Batey at the University of Toronto. The manuscript is divided into three chapters.Chapter one gives a general overview of methods for metal-catalyzed synthesis of heterocycles through carbon-heteroatom (C--Y) bond-forming events.Chapter two describes the intramolecular copper-catalyzed synthesis of 2aminobenzoxazoles through the coupling of aryl bromides with ureas. Reaction conditions were optimized through studies examining the effect of changing various reaction parameters including temperature, catalyst and ligand loadings, solvent choice, and degree of dryness of the reaction system. Optimized reaction conditions involve heating o-bromophenylurea precursors with 10 mol% copper iodide and 20 mol% 1,10-phenanthroline ligand in the presence of the weak base CS2CO3 (1.2 equiv) in a 1:1 acetonitrile:xylenes solvent system at 110-120°C to give 2-aminobenzoxazole products in good to excellent conversions and yields for a reaction time of 24 hours, These reactions were found to require strictly anhydrous reaction conditions and are effective only for N,N',N'-trisubstituted o-bromophenylureas.Chapter three describes a novel paliadium(0) catalyzed intramolecular oxidative C--H bond functionalization/C--S bond formation reaction for the synthesis of 2aminobenzothiazoles and related heterocycles. Reaction optimization studies were conducted by examining the effect of changing various reaction parameters while monitoring the progress of the reactions using HPLC. Optimized reaction conditions involve heating arylthiourea substrates with 3 mol% palladium tetrakistriphenylphosphine with activated 10 mol% manganese dioxide in acetonitrile solvent under an oxygen atmosphere at 80°C to give cyclized 2-aminobenzothiazole products in excellent yields. Anhydrous reaction conditions are required, and only N,N',N'-trisubstituted phenylthioureas were found to be suitable precursors to 2aminobenzothiazoles. This methodology offers improved efficiency and atom economy over previous metal-catalyzed methods that require ortho-halo arylthiourea precursors, thereby significantly improving the availability of phenylthiourea starting materials. Unlike for other palladium-catalyzed C--H functionalization reactions typically utilizing Pd(II) and a co-oxidant such as Cu(OAc)2 under oxidative conditions, we propose that the main role of activated MnO 2 is to act as a porous surface/sink to adsorb oxygen and deliver it to paliadium(0) to form a peroxo-paliadium(II) species.
Author: Laurie Lynn Joyce Publisher: ISBN: Category : Languages : en Pages : 906
Book Description
This thesis is a summary of research conducted in the laboratory of Professor Robert A. Batey at the University of Toronto. The manuscript is divided into three chapters.Chapter one gives a general overview of methods for metal-catalyzed synthesis of heterocycles through carbon-heteroatom (C--Y) bond-forming events.Chapter two describes the intramolecular copper-catalyzed synthesis of 2aminobenzoxazoles through the coupling of aryl bromides with ureas. Reaction conditions were optimized through studies examining the effect of changing various reaction parameters including temperature, catalyst and ligand loadings, solvent choice, and degree of dryness of the reaction system. Optimized reaction conditions involve heating o-bromophenylurea precursors with 10 mol% copper iodide and 20 mol% 1,10-phenanthroline ligand in the presence of the weak base CS2CO3 (1.2 equiv) in a 1:1 acetonitrile:xylenes solvent system at 110-120°C to give 2-aminobenzoxazole products in good to excellent conversions and yields for a reaction time of 24 hours, These reactions were found to require strictly anhydrous reaction conditions and are effective only for N,N',N'-trisubstituted o-bromophenylureas.Chapter three describes a novel paliadium(0) catalyzed intramolecular oxidative C--H bond functionalization/C--S bond formation reaction for the synthesis of 2aminobenzothiazoles and related heterocycles. Reaction optimization studies were conducted by examining the effect of changing various reaction parameters while monitoring the progress of the reactions using HPLC. Optimized reaction conditions involve heating arylthiourea substrates with 3 mol% palladium tetrakistriphenylphosphine with activated 10 mol% manganese dioxide in acetonitrile solvent under an oxygen atmosphere at 80°C to give cyclized 2-aminobenzothiazole products in excellent yields. Anhydrous reaction conditions are required, and only N,N',N'-trisubstituted phenylthioureas were found to be suitable precursors to 2aminobenzothiazoles. This methodology offers improved efficiency and atom economy over previous metal-catalyzed methods that require ortho-halo arylthiourea precursors, thereby significantly improving the availability of phenylthiourea starting materials. Unlike for other palladium-catalyzed C--H functionalization reactions typically utilizing Pd(II) and a co-oxidant such as Cu(OAc)2 under oxidative conditions, we propose that the main role of activated MnO 2 is to act as a porous surface/sink to adsorb oxygen and deliver it to paliadium(0) to form a peroxo-paliadium(II) species.
Author: Maria Gerelle Publisher: ISBN: Category : Languages : en Pages :
Book Description
Chapter 1 is a brief literature review of the most recent progress in the area of C-H functionalization via palladium catalysis. This covers the functionalization of electron deficient arenes and heterocycles with alkenyl and alkyl halides both using inter- and intra-molecular reactions. The chapter also contains an overview of recent work from the Willis group. Chapter 2 presents the functionalization of electron deficient arenes and alkenyl bromides using palladium catalysis (Scheme 1), as well as the use of statistical analysis software for optimizing the cross-coupling reaction. Scheme 1: Functionalization of electron deficient arenes using palladium catalysis Chapter 3 describes the cross-coupling of substituted benzoxazoles, benzothiazole and benzimidazole with a range of alkenyl iodides using palladium catalysis (Scheme 2). The reaction can tolerate both (E) and (Z) disubstituted alkenes and tri-substituted alkenyl iodides, with retention of the double bond geometry. 1 x =0, S, NMe - 14 examples 25-99% yield i Scheme 2: Cross-coupling using benzoxazoles, benzothiazole and benzimidazole with alkenyl iodides Chapter 4 details the synthesis of sultams via an intramolecular functionalization using palladium catalysis. The chapter covers the optimization of the starting material synthesis as well as the cross-coupling reaction. We can access the sulfonamides from cyc1ohexenone and were able to incorporate a large range of substitution patterns (Scheme 3). Scheme 3: Synthesis ofsultams from cyclohexenone Finally, Chapter 5 contains all the experimental details, general considerations and compound data. All the NMR spectra of novel compounds can be found in the appendix. 2.
Author: Aiwen Lei Publisher: John Wiley & Sons ISBN: 3527681000 Category : Technology & Engineering Languages : en Pages : 240
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: Gwilherm Evano Publisher: John Wiley & Sons ISBN: 1118060458 Category : Science Languages : en Pages : 851
Book Description
Providing comprehensive insight into the use of copper in cross-coupling reactions, Copper-Mediated Cross-Coupling Reactions provides a complete up-to-date collection of the available reactions and catalytic systems for the formation of carbon-heteroatom and carbon-carbon bonds. This essential reference covers a broad scope of copper-mediated reactions, their variations, key advances, improvements, and an array of academic and industrial applications that have revolutionized the field of organic synthesis. The text also discusses the mechanism of these transformations, the use of copper as cost-efficient alternative to palladium, as well as recently developed methods for conducting copper-mediated reactions with supported catalysts.
Author: Anant R. Kapdi Publisher: Elsevier ISBN: 0128052554 Category : Science Languages : en Pages : 502
Book Description
Strategies for Palladium-Catalyzed Non-directed and Directed C-H Bond Functionalization portrays the complete scope of these two aspects of C-H bond functionalization in a single volume for the first time. Featured topics include the influence of palladacyclic systems in C-H bond functionalization (need for newer catalytic systems for better efficiency), mechanistic aspect of the functionalization strategies leading to better systems, and applications of these methodologies to natural product synthesis and material synthesis. Addresses the involvement of catalytic systems (palladacycles) for better functionalization of (hetero)arenes to emphasize the need for developing better, more selective systems Covers the use of powerful mechanistic tools for understanding and assisting the development of better functionalization strategies Discusses the finer aspects of C-H bond functionalization, such as control of regioselectivity with or without directing groups Includes a chapter detailing the synthesis of naturally occurring molecules or functional molecules via both pathways for assessing the applicability of the functionalization strategies
Author: Xavi Ribas Publisher: Royal Society of Chemistry ISBN: 1849737169 Category : Science Languages : en Pages : 489
Book Description
Cross-coupling reactions involving C-H and C-X bond functionalisation are commonplace in natural product synthesis and natural products, therapeutic agents, biological probes, and advanced materials. Much attention has been given to understanding the mechanistic strategies used to achieve this, making this a hot topic in recent years. In this edited book, contributions from across the globe examine these strategies, with a particular focus on palladium and copper, as well as iron – an emerging element in this field. Reviewing the recent literature, the book presents an in-depth understanding of the field, guiding the reader to achieving the best synthetic strategies for aromatic functionalisation. Organic and Organometallic chemists, as well as natural product and pharmaceutical scientists, will find this an essential guide to a major transformation currently underway in synthetic chemistry.
Author: András Kotschy Publisher: Springer Science & Business Media ISBN: 9781402036248 Category : Science Languages : en Pages : 224
Book Description
"Heterocycles from Transition Metal Catalysis: Formation and Functionalization" provides a concise summary of the prominent role of late transition metal (palladium, nickel, copper) catalysed processes in the synthesis and functionalization of heterocyclic systems. It gives an introduction to catalytic transformations, an overview of the most important reaction types, and presents synthetically useful catalytic processes classified by the target system and the type of transformation. The book provides a representative selection of transition metal catalysed reactions transformations that are relevant in heterocyclic chemistry. In this way, the authors present a useful resource for members of the academic community looking for a textbook as well as industrial chemists in search of a reference book. This book will be an invaluable resource for synthetic chemists, medicinal chemists, and those more generally interested in applied catalysis.
Author: Christopher Scott Bryan Publisher: ISBN: Category : Languages : en Pages : 798
Book Description
Our group has developed a strategy for the synthesis of benzofused carbocycles and heterocycles through tandem palladium-catalyzed reactions of gem-dibromoolefins. In these syntheses, one bromide undergoes a Pd-catalyzed cyclization reaction, and the other participates in an orthogonal inter- or intramolecular Pd-catalyzed reaction to functionalize or annulate that ring, respectively.Chapter 2 describes the synthesis of benzothiophenes through the combination of a Pd-catalyzed C--S coupling with an orthogonal Suzuki, Heck, or Sonogashira reaction. This represents the first example of the incorporation of Pd-catalyzed C--S coupling into a tandem reaction.Chapter 1 describes the pairing of an intramolecular C--N bond forming reaction (the Buchwald- Hartwig coupling) with an intramolecular direct arylation for the synthesis of fused indole derivatives. A range of previously unknown heterocycles were synthesized through this method.In Chapter 3, a tandem intramolecular Heck / intermolecular Suzuki reaction is described for the synthesis of methyleneindenes. Studies on this reaction have provided advanced understanding of the mechanism, including how variation of the ligand controls the regioselectivity of the reaction.
Author: Laurie Lynn Joyce
Author: Laurie Lynn Joyce
Author: Xiao-Feng Wu
Author: Maria Gerelle
Author: Aiwen Lei
Author: Gwilherm Evano
Author: Debabrata Maiti
Author: Anant R. Kapdi
Author: Xavi Ribas
Author: András Kotschy
Author: Christopher Scott Bryan