Chemistry Commons^™

Water-Soluble Palladium, Copper, And Nickel Catalysts And Their Formation In Ligand-Free Suzuki-Miyaura Cross-Coupling Reactions, Priya Karna

Theses and Dissertations--Chemistry

Transition-metal catalyzed Suzuki-Miyaura (SM) cross coupling is a powerful synthetic method for constructing carbon-carbon and carbon-heteroatom bonds in designing organic compounds, agrochemicals, pharmaceuticals, and precursors for materials. However, the nature of catalysis and identity of the transition metal catalysts used in these reactions remain under debate or unknown. This dissertation reports the studies of three metals: Pd, Cu, and Ni. Pd-nanocluster catalysts and their formation in ligand-free SM reactions with Pd(II) nitrate as a precatalyst was investigated. The catalysts are water-soluble neutral Pd tetramer and trimer in their singlet electronic states as identified by UV-Vis absorption spectroscopy and are formed …

Biomimetic Synthesis Of Palladium Nanoparticles For Catalytic Application, Emily A. Groover

Electronic Theses and Dissertations

The synthesis of palladium nanoparticles (Pd NPs) using materials-directed peptides is a novel, nontoxic approach which exerts a high level of control over the particle size and shape. This biomimetic technique is environmentally benign, featuring nonhazardous ligands and ambient conditions. Nanoparticles are extremely reactive catalysts, boasting a large surface-to-volume ratio when compared to their bulk counterparts. The rational design of these nanoparticles using peptides has been very successful in aqueous environments, but no research has been done to apply it in organic systems. As such, the biomimetic synthesis of Pd NPs in an organic system is here investigated, with ethanol …

Asymmetric Alpha-Stannylation Of Heterocycles And Their Subsequent Use In Cross-Coupling Reactions, Haoran Zhao

Dissertations, Theses, and Capstone Projects

α-Substituted oxygen-containing heterocycles are commonly present in biologically active molecules. Statistics shows that at least one α-substituted ether moiety appears in over 20% of the top 200 small-molecule pharmaceuticals. This project illustrates a reliable regioselective method to introduce simple cyclic ethers towards the diversification of small molecules. Aryl halides bearing various functional groups were well tolerated independent of their electronic properties. It was found that cyclohexyl spectator ligands on tin selectively slows transmetallation of undesired units, circumventing the competitive transfer of n-butyl group from ⁿBu₃SnR reagents. Compared to the normally used ⁿBu₃SnR reagents, Cy …

Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph

Dissertations, Theses, and Capstone Projects

Organometallic reagents containing the tin-carbon bond are used extensively in modern synthetic chemistry for the formation of new bonds to carbon. Over recent decades, transition metal catalyzed cross coupling reactions between two C(sp²) centers have been widely developed. However, the introduction of a C(sp³) center complicates the catalytic cycle, and opens unproductive chemical pathways which lead to isomerization, elimination, and racemization. Our lab has developed a modified-Stille reaction to combat the deleterious effects of β-hydride elimination. Our protocol enables unactivated 2° alkyl organotin nucleophiles to undergo efficient cross coupling reactions with C(sp²) electrophiles, avoiding …

An Investigation Of Alkylboron Transmetallation In Palladium-Catalyzed Suzuki Reactions, Benjamin Murray

Dissertations, Theses, and Capstone Projects

Through the past 40 years, carbon-carbon cross-coupling reactions have greatly enhanced the ability of chemists to synthesize C(sp²)-C(sp²) bonds and more recently C(sp²)-C(sp³) bonds. In particular, the Suzuki reaction has proven to be invaluable with its high yields, good functional group tolerance, and low toxicity of reagents. One of the component steps of the catalytic cycle of this reaction is transmetallation, in which the nucleophilic species transfers its organic component to the metal center (generally palladium). The mechanism of transfer from primary alkylboron nucleophiles was studied in the 1990's via use of …

Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone

Graduate Theses, Dissertations, and Problem Reports

Hetero(element) carboxylation is an appealing transformation that involves the installation of CO2 and another hetero(element) in one step. This transition metal-catalyzed one-pot synthesis provides a route to achieve highly functionalized carboxylic acid products with an abundant and cheap C1 feedstock. This difunctionalization also avoids the use of reactive metal hydride species, which is a prominent limitation of hydrocarboxylation chemistry. A copper-catalyzed regioselective boracarboxylation of vinyl arenes has been developed to access pharmaceutically relevant β-boryl-α-aryl propionic acid products. One drawback of this reaction is the necessity for high catalyst loading to achieve catalytic turnover. To circumvent this issue, the reduction of …

Development Of Copper-Catalyzed Suzuki-Miyaura Coupling Using Alkylboron Reagents And Nickel-Catalyzed Alkene Dicarbofunctionalization Reactions, Prakash Basnet

Chemistry and Chemical Biology ETDs

This thesis is divided into two parts. The first part deals with the development of copper-catalyzed Suzuki-Miyaura coupling of alkylboron reagents for the first time. In the second part, we will discuss the development of novel nickel-catalyzed alkene dicarbofunctionalization reactions.

Part I. Cross-coupling reactions are versatile tools to form new carbon-carbon bonds and are widely used in the synthesis of various drug molecules, natural products and materials. However, these reactions are typically catalyzed by palladium, an expensive and rare metal which makes the reaction unsustainable in long-terms. Additionally, palladium-catalyzed cross-coupling reactions with alkylorganometallic reagents suffer from side reactions due to …

Catalytic Functionalization Of Organoaluminum Reagents And Olefins By Cross-Coupling With Copper And Nickel, Bijay Shrestha

Chemistry and Chemical Biology ETDs

This thesis is divided into two parts. The first part focuses on the Cu-catalyzed cross-coupling of organoaluminum reagents with organohalides. One of the most powerful tools for the construction of C-C bonds is cross-coupling. But, this reaction is predominantly catalyzed by Pd, a rare and expensive transition metal, which inevitably makes the process unsustainable in the long-term. Furthermore, Pd-catalyzed cross-coupling also shows low tolerance for alkyl and heteroaryl substrates because of β-hydride elimination and catalyst deactivation, respectively. Although these issues remain largely solved by using sterically hindered and electron-rich ligands, however making these types of ligands is synthetically challenging and …

The Modified Stereospecific Stille Reaction: Palladium-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Carbastannatranes, Chao-Yuan Wang

Dissertations, Theses, and Capstone Projects

Organic chemistry is present in all domains of everyday life, from polymer production to medicine. In order to synthesize complex compounds, it is often necessary to make new carbon-carbon bonds. Transition metal catalysts, particularly those derived from second and third row metals such as Pt, Pd, Rh, and Ir metals, display remarkable efficiency for the formation of carbon-carbon and carbon-heteroatom bonds. In the first chapter, introduction of transition metal-catalyzed cross-coupling reactions is given. While the formation of C(sp²)–C(sp²) bonds has been studied extensively, C(sp³)-C(sp²) bond formation still presents a challenge due to …

Synthesis Of Α, Β-Substituted Alkenylphosphonates From Α-Phosphonovinyl Triflates: I) Palladium Catalyzed Suzuki-Miyaura Cross-Coupling With Aryl Boronic Acids Ii) Palladium Catalyzed Reduction, Ronald Laryea Mensah

Master of Science in Chemical Sciences Theses

Alkenylphosphonates (vinylphosphonates) are important targets for R & D because they have interesting chemical, biological and pharmacological properties. Vinylphosphonates are used in synthesis, polymer applications, and have demonstrated potential as anticancer and antimicrobial agents.

Vinyl triflates are useful in organic synthesis and are referred to as pseudo-halides because they react in a manner similar to halides. Vinyl triflates have a broad range of synthetic utility because they undergo nucleophilic substitutions and transition metal-mediated reactions. There is a growing interest in using α-phosphonovinyl pseudo-halides in transition metal-mediated cross-coupling reactions as a means to synthesize α, β-substituted alkenylphosphonates. Over the past three …

Asymmetric Synthesis And Transition Metal-Catalyzed Cross-Coupling Arylations Of Selected Organolithiums, Barry Kyle Sharp

Graduate Theses and Dissertations

My former boss, Dr. Gawley, always loved to say, “The world is chiral” (à la Pasteur). From DNA and proteins to hands and feet, it is obviously true. Also, a wide variety of chemical products exist as single enantiomers. Advances in chemical technology have greatly accelerated asymmetric synthesis in the past quarter century, and namely, organolithiums, have been shown to provide a versatile route to chiral natural products and biologically active molecules. Versatility arises from the array of methods that produce a chiral organolithium. Dynamic thermodynamic resolution (DTR) is considered one of the most practical methods, but among the others …

Nickel-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Nucleophiles, Amruta Ajit Joshi

Dissertations, Theses, and Capstone Projects

In the first chapter, introduction of transition metal-catalyzed cross-coupling reactions has been given. These transition metal-catalyzed C-C bond forming reactions have been used extensively in organic synthesis. Among them, C(sp2)-C(sp2) bond forming reactions have been widely studied over decades. More recently, some reports have demonstrated the use of C(sp3) nucleophiles and electrophiles in cross-coupling reactions. However, use of secondary and tertiary alkyl nucleophiles has remained a challenge due to competitive β-hydride elimination and slow transmetallation of bulky secondary and tertiary alkyl organometallic nucleophiles.

In the second chapter, the first general nickel-catalyzed Negishi reaction for the cross-coupling of unactivated, acyclic secondary …

Towards The Design And Syntheses Of Novel Triads Comprising Single Robson-Type Macrocyclic Dicopper(Ii) Cores Flanked By Two Terminal Polypyridyl Ruthenium(Ii) Complexes., Leslie Shane Moody

Electronic Theses and Dissertations

Progress toward the syntheses of new tetranuclear bimetallic complexes of copper(II) and ruthenium(II) was realized. The designed triads comprise a central binuclear copper(II) complex with a tetraiminodiphenolate macrocyclic Robson-type compartmental ligand. In the envisioned complexes, the macrocyclic core is further functionalized by attachment of two polypyridyl ruthenium(II) complexes. A novel dibrominated dicopper(II) Robson complex was formed by the 2:2:2 condensation reaction of 4-bromo-2,6-diformylphenol and 1,3- diaminopropane with cupric chloride. Similarly, a new dibrominated dizinc(II) was synthesized from zinc tetrafluoroborate and the same diamine and dialdehyde. The new dicopper(II) complex did not heterocouple with borylated substrates under explored Suzuki reaction conditions. …

Studies Toward Improving The Reactivity And Chemoselectivity Of Chloroarenes In Palladium-Catalyzed Cross-Coupling Processes, Joseph P. Simeone

Seton Hall University Dissertations and Theses (ETDs)

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