A5000841015- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Radical Photochemical Reactions
- Crystallography and molecular interactions
- Asymmetric Hydrogenation and Catalysis
- Chemical Synthesis and Analysis
- Asymmetric Synthesis and Catalysis
- Evolution and Paleontology Studies
- Oxidative Organic Chemistry Reactions
- Axial and Atropisomeric Chirality Synthesis
- Catalytic C–H Functionalization Methods
- Surface Chemistry and Catalysis
- Analytical Chemistry and Chromatography
- Molecular spectroscopy and chirality
- Bat Biology and Ecology Studies
- Advanced Photocatalysis Techniques
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Fluorine in Organic Chemistry
- Advanced biosensing and bioanalysis techniques
- Click Chemistry and Applications
- Molecular Sensors and Ion Detection
- Synthesis and Catalytic Reactions
- Synthetic Organic Chemistry Methods
- Animal Ecology and Behavior Studies
- Polyoxometalates: Synthesis and Applications
Technical University of Munich
2019-2025
Heidelberg University
2012-2021
Laboratoire de Chimie de Coordination
2014-2021
Centre National de la Recherche Scientifique
2014-2021
Yale University
2017-2019
Ludwig-Maximilians-Universität München
2016-2018
Analytisches Laboratorium
2015
Heidelberg (Poland)
2015
Université Toulouse III - Paul Sabatier
2014
Université de Toulouse
2014
Abstract A challenging synthetic modification of PEPPSI‐type palladium pre‐catalysts consisting a stepwise incorporation one and two amino groups onto the NHC skeleton was seen to exert sequential enhancement electronic donor properties. This appears be positively correlated with catalytic performances corresponding complexes in Buchwald–Hartwig amination. is illustrated, for example, by quantitative amination 4‐chloroanisole morpholine within 2 h at 25 °C mol % catalyst/substrate ratio or...
A photochemical deracemization of 5-substituted 3-phenylimidazolidine-2,4-diones (hydantoins) is reported (27 examples, 69%-quant., 80–99% ee). The reaction catalyzed by a chiral diarylketone which displays two-point hydrogen bonding site. Mechanistic evidence (DFT calculations, radical clock experiments, H/D labeling) suggests the to occur selective atom transfer (HAT). Upon binding, one substrate enantiomer at stereogenic center photoexcited catalyst allowing for HAT from and eventually...
A visible-light-mediated, enantioselective approach to axially chiral alkenes is described. Starting from a racemic mixture, major alkene enantiomer formed due selective triplet energy transfer catalytically active sensitizer. catalyst loading of 2 mol % was sufficient guarantee consistently high enantioselectivities and yields (16 examples, 51%-quant., 81–96% ee). NMR studies DFT computations revealed that more rapid within the substrate–catalyst complex minor enantiomer. Since this...
Photoenzymatic catalysis facilitates stereoselective new-to-nature chemistry under mild conditions. In addition to the rational design of artificial photoenzymes, naturally occurring redox enzymes have been repurposed for this approach. Most prominently, flavin-containing cofactors can promote photoredox in chiral protein environment, with several examples enantioselective C–C bond forming reactions reported recent years. Here, we add another class natural enzymes, which utilize...
Abstract Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for preparation compounds. The separate synthesis both compounds requires tedious and time‐consuming or chiral separation racemic products. Here, we report a stereochemically flexible diastereomeric rhodium(I) catalyst asymmetric hydrogenations prochiral (Z)‐α‐acetamidocinnamates α‐substituted acrylates, which changes its enantioselectivity depending on temperature to produce each...
Determining the sequence and structure of peptides is crucial for understanding their structure–property relationships. Among many techniques, structures are typically elucidated using nuclear magnetic resonance spectroscopy single crystal X-ray diffraction measurements. In this study, we present terahertz time-domain (THz-TDS) as a complementary, nondestructive technique that sensitive to both primary secondary tetrapeptides. Using only few milligrams peptide, THz-TDS spectra have been...
Abstract The intramolecular [2+2] photocycloaddition of 3‐alkenyl‐2‐cycloalkenones was performed in an enantioselective fashion (nine representative examples, 54–86 % yield, 76–96 ee ) upon irradiation at λ =366 nm the presence AlBr 3 ‐activated oxazaborolidine as Lewis acid. An extensive screening proline‐derived oxazaborolidines showed that enantioface differentiation depends strongly on nature aryl group 3‐position heterocycle. DFT calculations acid–substrate complex indicate attractive...
Photoenzymatic catalysis facilitates stereoselective new-to-nature chemistry under mild conditions. In addition to the rational design of artificial photoenzymes, naturally occurring redox enzymes have been repurposed for this approach. Most prominently, flavin-containing cofactors can promote photoredox in chiral protein environment, with several examples enantioselective C–C bond forming reactions reported recent years. Here, we add another class natural enzymes, which utilize...
Abstract Highlights von November 2023 bis 2024: die erste Einelektron‐C–C‐σ‐Bindung und Anti‐Bredt‐Verbindung; gesättigte Heterocyclen elektrochemisch funktionalisieren; Ausrichten diskotischer Flüssigkristalle; enantioselektive Wagner‐Meerwein‐Umlagerung reiner Aliphaten; photokatalytisch Furanen zu Pyrrolen; mit Ammoniak primären Arylaminen; Metallschrott recyceln ionischen Flüssigkeiten; terminale Alkene Ni‐Katalysatoren zum (Z)‐ oder (E)‐Alken isomerisieren;neue Fungizide, Medikamente Alkaloide.
Abstract Dieser Trendbericht erläutert Erkenntnisse der letzten beiden Jahre aus Sicht von Wissenschaftlerinnen und Wissenschaftlern des interdisziplinären, durch die DFG geförderten Konsortiums Transregio 325. Die Autorinnen Autoren forschen vor allem zu chemischer Photokatalyse beleuchten besonders Themen mit molekülchemischer Komponente.
The rapid and direct determination of enantiomeric ratios is increasing interest due to the significantly reduced effort compared chromatographic methods large number analytes, for instance in enantioselective catalysis. Current strategies include colorimetric assays, (a)chiral solvating reagents NMR spectroscopy metal complexes CD sensing. We report based on self-induced diastereomeric anisochronism (SIDA) effect. Alanine derivatives that represent chiral products catalysis, such as...
Abstract The diverse activity of flavoenzymes in organic transformations has fascinated researchers for a long time. However, when applied outside an enzyme environment, the isolated flavin cofactor only shows largely reduced activity. This highlights importance embedding reactive isoalloxazine core flavins defined surroundings. latter include crucial non-covalent interactions with amino acid side chains or backbone as well controlled access to reactants such molecular oxygen. Nevertheless,...
Flavoenzymes mediate a multitude of chemical reactions and are catalytically active both in different oxidation states covalent adducts with reagents. The transfer such reactivity to the organic laboratory using simplified molecular flavins is highly desirable, applications (photo)oxidation already established. However, have not been used for reduction substrates yet, although this activity known well-studied DNA photolyase enzymes. We report catalytic method reduced as photoreductants...
Since the discovery of molecular chirality, nonsuperimposable mirror-image organic molecules have been found to be essential across biological and chemical processes increasingly in materials science. Generally, carbon centers containing four different substituents are configurationally stable, unless bonds stereogenic atom broken re-formed. Herein, we describe sp3-stereogenic carbon-bearing that dynamically isomerize, interconverting between enantiomers without cleavage a constituent bond,...
A dynamic axially chiral BIPHEP-ligand with 3,5-dichlorobenzoyl amide selector units for non-covalent binding of phenylalanine derivatives has been developed. Interaction studies in solution were performed rhodium(i) complexes under exclusion the metal being involved binding. (Rax, S(Phe)) and (Sax, adducts observed as significantly separated species NMR spectroscopy.
Catalytic desaturations are important strategies for the functionalization of organic molecules. In nature, flavoenzymes mediate formation α,β-unsaturated carbonyl compounds by concomitant cofactor reduction. Contrary to many laboratory methods these reactions, such as Saegusa-Ito oxidation, no transition metal reagents or catalysts required. However, a molecular flavin-mediated variant has not been reported so far. We disclose photochemical approach silyl enol ether which leads ketones (13...
Abstract Asymmetrische Katalyse mit enantiomerenreinen Katalysatoren ist eine der weitverbreitetsten Methoden zur Herstellung enantiomerenreiner Verbindungen. Die selektive Synthese beider Produkte erfordert dabei die aufwändige oder alternativ Enantiomerentrennung racemischer Produkte. Wir stellen einen stereodynamisch flexiblen diastereomeren Rhodium(I)‐Katalysator für asymmetrische Hydrierung prochiraler ( Z )‐α‐Acetamidozimtsäure‐ und α‐substituierter Acrylsäurederivate vor, seine...
Abstract A challenging synthetic modification of PEPPSI‐type palladium pre‐catalysts consisting a stepwise incorporation one and two amino groups onto the NHC skeleton was seen to exert sequential enhancement electronic donor properties. This appears be positively correlated with catalytic performances corresponding complexes in Buchwald–Hartwig amination. is illustrated, for example, by quantitative amination 4‐chloroanisole morpholine within 2 h at 25 °C mol % catalyst/substrate ratio or...
Configurationally stable, atropisomeric motifs are an important structural element in a number of molecules, including chiral ligands, catalysts, and molecular devices. Thus, understanding features that stabilize axes is fundamental interest throughout the chemical sciences. The following details high rotational barriers about Ar–C(O) bond tropone amides, which significantly exceed those analogous benzamides. These studies supported by both experimental computational barrier measurements. We...
Abstract A straightforward synthesis of novel chiral polysiloxane‐based metal stationary phases immobilized through a propylenoxy linker (Chirasil‐Metal‐OC 3 ) to the polymeric backbone is presented. Synthesis was accomplished in six steps with high overall yields starting from commercially available, enantiopure (+)‐(1 S )‐camphorsulfonic acid. Two different approaches towards Chirasil‐Metal featuring either or propylenthio used for immobilization hydrosilylation are Furthermore, new...