Browsing Naturwissenschaften, Mathematik und Informatik by Referee "Walker, Johannes C. L. Prof. Dr."
Now showing items 1-20 of 24
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Metallaelectro-Catalysis and Aryl Sulfonium Salts in Sustainable C–H Activations and Late-Stage Diversification
(2024-09-17)In the past decades, organic chemistry was dominated by functional group interconversions and cross-coupling chemistry. These techniques allowed the synthesis of a plethora of highly complex molecules and are established ... -
Development of Bone Adhesive Materials based on Collagen-mimetic Peptides and Carbene-mediated Diazirine Crosslinkers
(2024-08-22)Traditional mechanical fixation methods such as screws, support plates, staples, and sutures remain predominant in treating bone trauma. However, these methods can cause localized tissue damage, leading to infection and ... -
Synthesis of Novel Sulfur(VI) Reagents and the Regioselective Functionalization of Helicenes by Hypervalent Reagents
(2024-06-28)The synthesis of novel sulfur(VI) reagents was investigated. For this purpose different sulfurane oxides were synthesized. The functionalization of these compounds was unsuccessful due to decomposition or inertness of the ... -
meta-C−H Functionalization and Sustainable Electro- /Photoelectrocatalytic C−H/Si−H/Ge−H Activation
(2024-06-18)C−H activation provides a crucial new tool for the construction of C−C bonds in organic chemical synthesis, especially for agrochemistry, the pharmaceutical industry, and materials science, using a large number of existing ... -
Exploiting the Disulfide/Thiol Switch for Photoinduced Proton-Coupled Multielectron Transfer Reactivity
(2024-03-27)Energy storage and efficient release has become a pivotal issue for our society relying progressively on renewable energy sources. The dichotomy between harvesting the sun’s energy in daylight hours, and requiring it the ... -
Towards an Effective Synthesis of Functionalized Heptacyclo[6.6.0.02,6.03,13.04,11.05,9.010,14]tetradecane
(2024-03-14)A reassessment of the Rh-catalyzed dimerization of norbornadiene to generate heptacyclo[6.6.0.02,6.03,13.04,11.05,9.010,14]tetradecane (HCTD), a carbocyclic cage compound, has been conducted introducing novel π-acceptor ... -
Sustainable Methods in C–H Functionalizations
(2023-05-30)Cross-coupling chemistry has matured in an attractive tool in synthetic organic chemistry to realized efficient formation of C‒C and C‒Het bonds. However, these transformations are also associated with certain drawbacks, ... -
Electrochemical Benzylic C−H Fluorination and 4d-Metallaelectro-Catalyzed C−H and C−C Functionalizations
(2023-03-15)Direct functionalizations of C−H and C−C bonds have emerged as time-saving and cost-effective alternatives to established cross-coupling reactions. However, oxidative coupling variants require stoichiometric amounts of ... -
Tetradentate NHC/Thiolato and NHC/Alcoholato Hybrid Scaffolds – A Nickel(II) Complex as Bidentate Metalloligand in 3d Transition Metal Chemistry
(2023-03-08)Research and development of N-heterocyclic carbene (NHC)-based ligands has flourished in recent decades. Herein, The new bis-imidazolinium proligands were designed and synthesized to serve as tetradentate bis(NHC)-dithiolato ... -
Fixing the Conformation in Helicenes: Enantioselective Synthesis of [5]Helicenes and Synthesis of In-Fjord Substituted Expanded Helicenes
(2022-12-16)By combining the 3,3’-disubstituted BINOL-derived backbone and different cationic rests, a new family of α-cationic chiral phosphonites has been synthesized. Coordination to Au(I) afforded the corresponding precatalysts. ... -
Tuning the donor properties of bipyridyl-substituted phosphines by metal ion encapsulation & Photocatalytic synthesis of 6H-benzo[c]chromenes from S-aryl sulfonium salts
(2022-11-09)This work is divided into two parts. The first part introduces a novel approach for the synthesis of cationic phosphine ligands by metal ion encapsulation. In this context, multidentate heterophosphines encapsulate a ... -
C–H Activation via Iridium and Rhodium Electrocatalysis and Undirected Electrochemical Fluorination
(2022-06-24)In past decades, transition metal-catalyzed C–H activation has emerged as an increasingly viable toolbox for the step- and atom economic formation of C–C and C–Het bonds. However, oxidative C–H transformations heavily rely ... -
Searching for more π-acceptor phosphines: From α-pyridiniophosphines to α-cationic phospholes
(2022-04-07)This thesis focuses on two classes of cationic phosphines. In the first part, the previously developed cationic pyridinio-phosphines were investigated further in respect to their coordination chemistry towards Ir and their ... -
Application of Asymmetric Gold-Catalyzed Hydroarylation in the Enantioselective Synthesis of Helicenes
(2022-04-07)A novel family of electron deficient, α-cationic ligands was synthesized, combining a chiral TADDOL-backbone with an electron withdrawing 1,2,3-triazolium moiety. Coordination to Au(I) gave the respective catalysts. Both ... -
Late-Stage Peptide Functionalization by Transition Metal-free and Palladium-Catalyzed C–H Arylations
(2022-03-31)The focus of this thesis was set on the late-stage modification of peptides through transition metal-free and palladium-catalyzed C–H arylations. At first, the scope of the transition metal-free C2-arylation of the ... -
Molecular Ruthenium based Water Oxidation Catalysts and their Immobilization on Electrode Surfaces
(2022-02-11)Ruthenium complexes are valuable in the field of catalytic water oxidation. Their stability and molecular nature allow for detailed mechanistic insight, and they can be synthetically modified to enhance their activity. ... -
Merging Electrosynthesis with 3d Transition Metal-Catalyzed C–H Transformations
(2021-07-12)In recent years, oxidative C–H transformations have emerged as increasingly powerful tools in molecular syntheses. However, despite great progress towards more atom and step economic synthetic methods, oxidative couplings ... -
S-Substituted Dibenzothiophenium Triflates: Synthesis, Structure and Reactivity
(2021-04-23)The content of this thesis focused on the general syntheses and applications S-substituted alkynyl-, alkenyl- and aryldibenzothiophenium triflates. Addition reactions have been performed from S-alkynyldibenzothiophenium ... -
Selective C–H Activation by Ruthenium(II) Carboxylate and Nickelaelectro-Catalysis
(2021-01-28)This doctoral thesis was divided into two main parts. In the first part, ruthenium(II)-catalyzed ortho-C–H alkynylations of diverse benzoic acids were achieved for the synthesis of aromatic alkynes. And meta-C–H activations, ... -
Synthesis and reactivity of succinylthioimidazolium salts: A unified strategy for the preparation of thioethers
(2020-12-21)Sulfur is one of the main group elements on our planet with a natural abundance of (0.46±0.15)w%. In its most common allotropic form sulfur is a yellow powder and exhibits a cyclic S8 structure. Apart of the cyclic S8 ...