Synthesis and Palladium-catalyzed Carbonylation of Substituted Vinyl Triflates PDF Download

Author: Adam Gerherd). Meyer
Publisher:
ISBN:
Category :
Languages : en
Pages : 360

View

Book Description
Studies the synthesis of substituted hydraxy and amino vinyl triflates and their applicability to undergo an intramolecular palladium-catalyzed carbonylation reaction. Optically active monocyclic and bicyclic [alpha], [beta]-unsaturated [ga-lactones and the monoterpene(+) mintlactone were synthesized.

Author: Yi Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"Transition metal catalyzed carbonylation reactions have been broadly exploited for the synthesis of carbonyl-containing products. A versatile version of these are palladium-catalyzed carbonylative coupling reactions of organic halides and nucleophiles. However, one drawback to this chemistry is the low electrophilic reactivity of the palladium-acyl intermediates in reaction, which severely limits the scope of nucleophiles that can be employed in carbonylations. This thesis describes studies to address this challenge by the formation of potent acyl electrophiles via metal-catalyzed carbonylations, and their use with non-classical carbonylation nucleophiles. In chapter 2, we demonstrate how the correctly ligated palladium catalyst can be used to create potent acyl-pyridinium electrophiles via the carbonylation of aryl or vinyl triflates, and use these for in situ (hetero)arene C-H bond functionalization. The reaction was catalyzed by a Xantphos-coordinated palladium catalyst, and the bidentate and large-bite-angle ligand is believed to balance the activation of the strong C(sp2)-OTf bonds with the reductive elimination of reactive N-acyl-pyridinium electrophiles. The pyridine employed not only leads to the formation of the acyl-pyridinium salt electrophile, but its structure can be used to modulate selectivity in arene C-H functionalization. Overall, this offers a carbonylative method to form diaryl ketones, [alpha],[beta]-unsaturated ketones, and polycyclic ketones using a broad range of aryl- or vinyl- triflates and (hetero)arenes. Chapter 3 describes an extension of the work in chapter 2, where simple lithium chloride rather than the specialized trifluoromethyl- or methoxy-substituted pyridine can be used as the additive for the palladium catalyzed carbonylative coupling of aryl or vinyl triflates and heteroarenes to form ketones. Mechanistic studies suggest the reaction proceeds by the catalytic generation of acid chloride electrophiles for functionalization of electron-rich heterocycles.A limitation to the carbonylative generation of acyl electrophiles noted above is the need to use aryl- or vinyl-(pseudo)halides as reagents. The association of carbon monoxide to the catalyst severely inhibits oxidative addition reactions, and blocks the use of less reactive substrates such as alkyl halides. In chapter 4, we design a strategy to address these challenges using visible light excitation of palladium. This has opened an approach to perform the carbonylation of diverse array of aryl- and even alkyl-halides and from these build-up acid chlorides with the ability to reaction with various nucleophiles. Mechanistic studies suggest the reaction proceeds via a unique combination of photoevents, where the photoexcitation of Pd(0) induces electron transfer with the organic halide to favor oxidative addition, while the photoexcitation of the Pd(II) intermediate leads to Pd-acyl bond scission and the ultimate reductive elimination of acid chloride electrophiles. While the results in chapter 4 expand the variety of products available from carbonylation, the formation of acid chlorides as reaction products (rather than intermediates) is usually not possible. The latter can be attributed to the high reactivity of acid chlorides, which can lead to their rapid re-addition to the palladium catalyst and either inhibit the reaction or lead to their slow decomposition. In chapter 5, we developed a method to address these limits via the synthesis of less easily reduced acyl fluorides. In this case, mechanistic studies suggest visible light favored oxidative addition to Pd(0) is coupled with rapid ligand driven reductive elimination of the acyl fluoride product, which does not re-add to the Pd(0) once formed. By driving these two reverse steps with different inputs, this has offered a general platform to access acyl fluoride electrophiles, and from these synthesize complex, highly functionalized carbonyl-containing products"--

Author: H.M. Colquhoun
Publisher: Springer Science & Business Media
ISBN: 1475795769
Category : Science
Languages : en
Pages : 295

View

Book Description
Since the publication of our earlier book on transition metal mediated organic synthesis, * there has been a widespread increase of interest in this topic, and transition metal based methodology has become firmly established in many areas of organic chemistry. The direct, catalytic formation of organic carbonyl compounds using carbon monoxide as the source of the carbonyl group has seen exceptional progress, and this carbonylation chemistry is being used increasingly in research and on a larger scale for fine chemicals production. In view of these developments, there is a need for a modem, practi cally oriented book dealing with transition metal based carbonylation chemistry. The present monograph should help fulfill this need, since it is intended specifically to foster the adoption of catalytic carbonylation as a general tool in synthetic organic chemistry. It deals exclusively with reactions involving the interconversion of carbon monoxide and organic carbonyl compounds, and although the majority of the reactions discussed involve catalytic formation of carbonyl compounds, potentially valuable syntheses requiring stoichiometric quantities of transition metal are also included. In addition, a chapter is devoted to the remarkably useful reverse transformation (decarbonylation), in which an organic carbonyl group is eliminated in the form of carbon monoxide.

Author: Ei-ichi Negishi
Publisher: John Wiley & Sons
ISBN: 0471473812
Category : Science
Languages : en
Pages : 1657

View

Book Description
Organized to provide maximum utility to the bench synthetic chemist. The editor is well-known for his work in exploring, developing, and applying organopalladium chemistry. Contributors include over 24 world authorities in the field.

Author: Jie Jack Li
Publisher: Elsevier
ISBN: 0080465846
Category : Science
Languages : en
Pages : 662

View

Book Description
Palladium chemistry, despite its immaturity, has rapidly become an indispensable tool for synthetic organic chemists. Heterocycles are of paramount importance in the pharmaceutical industry and palladium chemistry is one of the most novel and efficient ways of making heterocycles. Today, palladium-catalyzed coupling is the method of choice for the synthesis of a wide range of biaryls and heterobiaryls. The number of applications of palladium chemistry to the syntheses of heterocycles has grown exponentially. These developments highlight the need for a monograph dedicated solely to the palladium chemistry in heterocycles and this book provides a comprehensive explanation of the subject. The principal aim of the book is to highlight important palladium-mediated reactions of heterocycles with emphasis on the unique characteristics of individual heterocycles. 1. Palladium chemistry of heterocycles has its “idiosyncrasies stemming from their different structural properties from the corresponding carbocyclic aryl compounds. Even activated chloroheterocycles are sufficiently reactive to undergo Pd-catalyzed reactions. As a consequence of &agr and &bgr activation of heteroaryl halides, Pd-catalyzed chemistry may take place regioselectively at the activated positions, a phenomenon rarely seen in carbocyclic aryl halides. In addition, another salient peculiarity in palladium chemistry of heterocycles is the so-called "heteroaryl Heck reaction". For instance, while intermolecular palladium-catalyzed arylations of carbocyclic arenes are rare, palladium-catalyzed arylations of azoles and many other heterocycles readily take place. Therefore, the principal aim of this book is to highlight important palladium-mediated reactions of heterocycles with emphasis on the unique characteristics of individual heterocycles. 2. A myriad of heterocycles are biologically active and therefore of paramount importance to medicinal and agricultural chemists. Many heterocycle-containing natural products (they are highlighted in boxes throughout the text) have elicited great interest from both academic and industrial research groups. Recognizing the similarities between the palladium chemistry of arenes and heteroarenes, a critical survey of the accomplishments in heterocyclic chemistry will keep readers abreast of such a fast-growing field. We also hope this book will spur more interest and inspire ideas in such an extremely useful area. This book comprises a compilation of important preparations of heteroaryl halides, boranes and stannanes for each heterocycle. The large body of data regarding palladium-mediated polymerization of heterocycles in material chemistry is not focused here; neither is coordination chemistry involving palladium and heterocycles. Many heterocycle-containing natural products (highlighted throughout the text) have elicited great interest from both academic and industrial research groups. Recognizing the similarities between the palladium chemistry of arenes and heteroarenes, a critical survey of the accomplishments in heterocyclic chemistry keeps readers abreast of this fast-growing field. It is also hoped that this book will stimulate more interest and inspire new ideas in this exciting area. Contains the most up-to-date developments in this fast-moving field Includes 3 new chapters Incorporates material from selected well-respected authors on heterocyclic chemistry

Author: Gwilherm Evano
Publisher: John Wiley & Sons
ISBN: 1118060458
Category : Science
Languages : en
Pages : 851

View

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: Gabriel Tojo
Publisher: Springer Science & Business Media
ISBN: 038725725X
Category : Science
Languages : en
Pages : 388

View

Book Description
The aim of this book is to help people performing routine operations in Organic Synthesis in a laboratory. This book, the first one in a series, focuses on the oxidation of alcohols to aldehydes and ketones. Probably, this is the most important routine operation in Organic Synthesis.

Author: László Kollár
Publisher: John Wiley & Sons
ISBN: 3527621555
Category : Science
Languages : en
Pages : 383

View

Book Description
Comprehensively covering modern carbonylation chemistry, this book is an indispensable companion for all synthetic chemists working in industry and academia. This monograph contains everything there is to know from recent advances in the investigation of carbonylation catalysts, via coordination chemistry to the synthetic application of transition metal catalyzed carbonylations.

Author: Gerardo Martin Torres
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"Metal catalyzed carbonylation reactions are heavily exploited in synthetic chemistry. These include not only high volume industrial reactions, but also a plethora of catalytic small molecule syntheses. This thesis will describe our efforts to develop such reactions. In these, palladium catalyzed carbonylations are exploited to build-up reactive products such as acid chlorides or carbonyl-containing 1,3-dipoles. Coupling this with the ability of the products undergo other spontaneous reactions can offer new routes to build up products from combinations of available reagents or be used to expand the scope of carbonylation chemistry. In chapter 2, we describe how the palladium catalyzed carbonylation of aryl iodides in the presence of imines can allow the overall generation of a 1,3-dipole: a Münchnone. A variety of mechanistic studies were performed on this reaction and show that it proceeds via a tandem catalytic process: the first involving the Pd catalyzed coupling of aryl iodides with carbon monoxide and a chloride salt to form an acid chloride, which can react with an imine and then undergo a second spontaneous cyclocarbonylation to afford the product. Coupling their formation with alkyne cycloaddition can be used to develop a novel method to assemble broad families of pyrroles from aryl iodides, imines, carbon monoxide and alkynes. In Chapter 3 we develop a strategy to apply our palladium catalyzed carbonylative synthesis of Münchnones to construct more complex pyrrole structures. In this, the combination of alkyne-tethered imines, aryl iodides, and carbon monoxide generates a Münchnone that can undergo intramolecular 1,3-dipolar cycloaddition to generate polycyclic pyrroles. This approach allows the modular and regioselective synthesis of complex pyrrole structures, and is compatible with less activated alkynes. In addition, we show that this reaction can be used in tandem with the palladium catalyzed Sonogashira functionalization of terminal alkynes with aryl iodides.In Chapter 4 we describe our efforts to take advantage of the ketene-like reactivity of Münchnones to generate [beta]-lactams. This transformation occurs via the palladium catalyzed formation of Münchnones from imines, aryl iodides, and carbon monoxide, followed by a cycloaddition to a second equivalent of imine to afford amide substituted [beta]-lactam products. Moreover, applying the conditions described in Chapter 2 for the synthesis of Münchnones allowed us to construct more diversely substituted [beta]-lactams by reacting the Münchnone with a different imine. Alternatively, the palladium catalyzed carbonylation of imine-tethered aryl iodides leads to the formation of novel spirocyclic [beta]-lactams.The palladium catalyzed synthesis of acid chlorides is a key component to the synthetic approaches to heterocycles presented in Chapters 2-4. However, the specific features that enable the catalyst to mediate the challenging reductive elimination of acid chlorides also inhibit the reverse oxidative addition step. In Chapter 5 we address these limitations by approaching this palladium catalyzed reaction from a different perspective. In this, visible light is used to drive both key steps in palladium catalysis: oxidative addition and reductive elimination. Analogous to other reports, we show that visible light excitation of a Pd complex can drive oxidative addition of a wide variety of aryl and alkyl halides. In addition, we find that visible light can induce a new reaction step the reductive elimination of acid chlorides. The latter occurs via the excitation in this case of the palladium-acyl intermediate. Together, this offers a platform to perform palladium catalyzed carbonylations at ambient temperature, with a wide array of organic halide substrates that have proven to be challenging in traditional palladium catalysis, and form from these acid chloride electrophiles that can allow the use of nucleophiles that are typically incompatible with carbonylations"--

Author: Navjeet Kaur
Publisher: CRC Press
ISBN: 1351242601
Category : Medical
Languages : en
Pages : 432

View

Book Description
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.