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Full-Text Articles in Organic Chemistry

An Investigation Of Alkylboron Transmetallation In Palladium-Catalyzed Suzuki Reactions, Benjamin Murray May 2019

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

All 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 ...


Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph May 2019

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

All 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 ...


Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone Jan 2019

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 ...


Development Of Copper-Catalyzed Suzuki-Miyaura Coupling Using Alkylboron Reagents And Nickel-Catalyzed Alkene Dicarbofunctionalization Reactions, Prakash Basnet Nov 2018

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

Chemistry 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 Jul 2018

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

Chemistry 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 ...


Enantioselective Γ- And Δ -Borylation Of Unsaturated Carbonyl Derivatives: Synthesis, Mechanistic Insights, And Applications., Gia L. Hoang Aug 2017

Enantioselective Γ- And Δ -Borylation Of Unsaturated Carbonyl Derivatives: Synthesis, Mechanistic Insights, And Applications., Gia L. Hoang

Student Research Projects, Dissertations, and Theses - Chemistry Department

Chiral boronic esters are valuable synthetic intermediates widely used in a variety of stereospecific transformations. Transition metal-catalyzed asymmetric hydroboration (CAHB) of alkenes is among the most popular methods for their preparation. Enantioselective hydroboration of activated alkenes (i.e., vinyl arene derivatives or conjugated carbonyl compounds) have been extensively studied by many research groups. We, on the other hand, are interested in enantioselective hydroboration of unactivated alkenes utilizing coordinating functional groups (e.g., carbonyl derivatives) to give functionalized, chiral boronic esters. While conjugate addition and C–H activation methodologies provide efficient alternatives to CAHB for enantioselective beta-borylation of carbonyl compounds, direct ...


The Modified Stereospecific Stille Reaction: Palladium-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Carbastannatranes, Chao-Yuan Wang Jun 2017

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

All 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 ...


Asymmetric Synthesis And Transition Metal-Catalyzed Cross-Coupling Arylations Of Selected Organolithiums, Barry Kyle Sharp Jul 2015

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

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 ...


Part I: Synthesis And Chemistry Of 2-Aryl-2-Nitroacetates Part Ii: Development Of Anion-Binding Catalysts Part Iii: Analysis Of An Axial Chiral Tetrachlorinated Bisbenzo[A]Phenazine, Alison E. Metz Jan 2015

Part I: Synthesis And Chemistry Of 2-Aryl-2-Nitroacetates Part Ii: Development Of Anion-Binding Catalysts Part Iii: Analysis Of An Axial Chiral Tetrachlorinated Bisbenzo[A]Phenazine, Alison E. Metz

Publicly Accessible Penn Dissertations

PART I. There are few reports on the synthesis of 2-aryl-2-nitroacetates, highlighting a need for development in this area. This section describes a high-throughput experimentation (HTE) approach to discover suitable conditions for the coupling of aryl bromides and α-nitroacetates to generate 2-aryl-2-nitroacetates. The best reaction conditions are 2.5 mol % Pd2dba3•CHCl3, 10 mol % t-BuXPhos, 1.2 equiv CsHCO3 in toluene at 75 °C, which afford products in isolated yields of 52–96%.

2-Aryl-2-nitroacetates are central precursors to other small molecules making them valuable building blocks in synthesis. Efficient methods were developed for the conversion of 2-aryl-2-nitroacetates to several product ...


Nickel-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Nucleophiles, Amruta Ajit Joshi Feb 2014

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

All 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 ...


Activation And Catalytic Bond Forming Reactions At Carbon-Hydrogen Bonds Of Η6-Tricarbonylchromium-Coordinated Benzylic Arenes, Genette I. Mcgrew Dec 2011

Activation And Catalytic Bond Forming Reactions At Carbon-Hydrogen Bonds Of Η6-Tricarbonylchromium-Coordinated Benzylic Arenes, Genette I. Mcgrew

Publicly Accessible Penn Dissertations

Polyarylmethanes are an extremely valuable molecular scaffold used in fields ranging from materials chemistry to medicinal chemistry. They are found in dyes and semiconductor dopants and in drugs and drug precursors that address a variety of ailments ranging form depression and allergies to cancer and vascular disease. However, general, selective methods to synthesize polyarylmethanes are still limited. This dissertation describes some of the exploratory work done to outline the synthetic possibilities of deprotonated tricarbonylchromium-stabilized benzylic arenes in the context of selective bond-forming reactions to form polyarylmethanes. Various η6-arene-tricarbonylchromium complexes are deprotonated with the mild silamide base LiN(SiMe ...


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 Dec 2008

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 ...


Studies Toward Improving The Reactivity And Chemoselectivity Of Chloroarenes In Palladium-Catalyzed Cross-Coupling Processes, Joseph P. Simeone Jan 2007

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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