Review
Chemistry, Medicinal
Ken Okuno, Ryuichi Nishiyori, Koki Abe, Taiki Mori, Seiji Shirakawa
Summary: Chiral 2-oxazolidinones are considered to be important heterocycles in medicinal chemistry, and many important pharmaceutical molecules are based on them. Therefore, the development of more efficient catalytic methods for synthesizing chiral 2-oxazolidinones is crucial in synthetic organic chemistry. This review summarizes the coupling reactions of epoxides and isocyanates for the preparation of 2-oxazolidinones, and introduces a synthetic example of a commercially available pharmaceutical compound using this method.
Article
Chemistry, Multidisciplinary
Chenxiao Qian, Pengfei Li, Jianwei Sun
Summary: A catalytic enantioselective variant of oxidative rearrangement of indoles to access oxindoles has been developed using chiral phosphoric acid catalysis, providing a rapid access to a range of enantioenriched spirooxindoles with high enantioselectivity controlled by dynamic kinetic resolution.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Viera Polackova, Dominika Kristofikova, Boglarka Nemethova, Renata Gorova, Maria Meciarova, Radovan Sebesta
Summary: Bifunctional N-sulfinylureas and thioureas with an appended pyrrolidine unit were synthesized and evaluated as organocatalysts in Michael additions. The N-sulfinyl-urea catalyst was more efficient than the corresponding thiourea, achieving up to 98% ee enantioselectivities for some substrates. The mode of action was elucidated through DFT calculations, confirming a dual activation mode involving enamine activation of aldehydes and hydrogen-bond activation of nitroalkenes.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Qi Zhang, Aiyou Hao, Pengyao Xing
Summary: In this study, the impact of solvent migration on molecular folding and chirality during thermal annealing was investigated. It was found that solvent migration from organic solvents to aqueous media resulted in a chiroptical inversion. Furthermore, the migration of solvents from aggregates to bulky phases led to a rearrangement of molecular packing and luminescent changes. Overall, consecutive chiroptical inversion was achieved using solvent strategy and thermal annealing.
Article
Chemistry, Multidisciplinary
Chang-Qiu Guo, Chuan-Jun Lu, Li-Wen Zhan, Peng Zhang, Qi Xu, Jia Feng, Ren-Rong Liu
Summary: This study reports a new catalyst that successfully catalyzes the enantioselective coupling reaction between quinone esters and anilines, resulting in the formation of N-aryl quinone atropisomers with a unique intramolecular hydrogen bond. This method has the potential to be used for the synthesis of structurally diverse secondary amine atropisomers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Multidisciplinary
Rosa Lopez, Claudio Palomo
Summary: This Minireview highlights the limited but significant catalytic methods for the generation of planar chirality in strained molecules, and serves as an inspiration for the development of new unconventional procedures in the future.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Dorian Sonet, Matteo Cayla, Raphael Mereau, Estelle Morvan, Aline Lacoudre, Nicolas Vanthuyne, Muriel Albalat, Dario M. Bassani, Antoine Scalabre, Emilie Pouget, Brigitte Bibal
Summary: The effects of introducing chiral trifluoromethyl alcohol groups on the physical properties and reactivity of 9,10-diphenylanthracenes were investigated. It was found that the position and orientation of the -CH(OH)CF3 groups in the molecules depend on the relative and absolute configurations of each stereoisomer. The study demonstrated that stereochemistry governs the molecular organization in crystals and impacts the reaction products, as well as modulates the chiroptical properties.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Hui Shen, Zhen Xu, Lingzheng Wang, Ying-Zi Han, Xianhu Liu, Sami Malola, Boon K. Teo, Hannu Hakkinen, Nanfeng Zheng
Summary: The study introduces a novel synthetic strategy to successfully synthesize tertiary chiral nanostructures with 100% optical purity. These structures consist of tri-metallic superatoms with inherent chirality and fair stability, driven by C-H...F interaction during self-assembly.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Manuel Weh, Jessica Ruehe, Benedikt Herbert, Ana-Maria Krause, Frank Wuerthner
Summary: The deracemization process of a racemic mixture of chiral molecules into enantioenriched compounds is achieved by an inherently chiral perylene bisimide cyclophane, which can transform [5]-helicene into an enantioenriched mixture with a high enantiomeric excess. The macrocyclic supramolecular host shows strong and enantioselective binding towards homochiral carbohelicenes, suggesting potential applications in template-catalyzed deracemization processes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Rosa Lopez, Claudio Palomo
Summary: N,N-Diacylaminals are flexible molecular scaffolds commonly used as amide surrogates in peptidomimetics. Recently, their singularity as an N-acyl imine equivalent and hydrogen-bond donor has led to new synthetic opportunities, particularly in the field of asymmetric catalysis. This concept article highlights the diverse synthetic potential of N,N-Diacylaminals and provides the necessary elements for further developments.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Grazia Bencivenni, Diana Salazar Illera, Maria Moccia, K. N. Houk, Joseph A. Izzo, Johanna Novacek, Paolo Grieco, Mathew J. Vetticatt, Mario Waser, Mauro F. A. Adamo
Summary: Through H-1 NMR titration experiments, it was found that chiral ammonium salts interact with substrates through specific C-H positions, providing a new rationale for rationalizing the enantioselectivity in chiral phase-transfer catalysis.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Beatrice Bartolomei, Vasco Corti, Maurizio Prato
Summary: In this study, a microwave synthesis method was used to produce a new type of chiral Carbon Nanodots (CNDs), which showed interesting absorption and emission properties and exhibited enantioselective organocatalytic reactions. The CNDs also displayed redox and light-absorbing properties suitable for driving photochemical processes. The CNDs were used as catalysts to promote cross-dehydrogenative coupling, demonstrating their potential to replace molecular catalysts in multiple reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Michela Lupi, Omar Salmi, Caterina Viglianisi, Stefano Menichetti
Summary: This article reports the conversion of N-thiophthalimido-arylphenothiazines 2 and triarylamines 3 to dithiabridged triarylamine hetero[4]helicenes 1 using catalytic amounts of chalcogen substituted Lewis Bases and hexafluoro isopropanol as hydrogen bond donor. The procedure provides good yields under mild reaction conditions without the need for excess Lewis Acids. It also presents a preliminary study on the control of the M and P absolute stereochemistry of helicenes 1 using enantiopure sulfur containing Lewis Bases from the natural chiral pool.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Da Xu, Yu Chang, Yidong Liu, Wenling Qin, Hailong Yan
Summary: This study achieved the enantioselective construction of stable VQM intermediates through organocatalyzed bromination, and revealed the mechanistic details of the two sequential events in VQM-involved reactions. The high potential of VQM as axially chiral synthetic reagents in organic chemistry was demonstrated.
Article
Chemistry, Inorganic & Nuclear
Jing Zhang, Frederic Aribot, Jean-Claude Chambron, Nathalie Zorn, Emmanuelle Leize-Wagner, Marion Jean, Nicolas Vanthuyne, Enrique Espinosa, Emmanuel Aubert
Summary: Cyclotribenzylenes (CTBs) with carbonitrile and alkyne substituents were synthesized and resolved into enantiomers using HPLC. Platinum-bridged CTB dimers were prepared from these compounds, forming Pt-alkynyl bonds in cis configuration. Mass spectrometry and NMR spectroscopy analysis revealed that racemic CTBs resulted in mixtures of diastereoisomers, while resolved CTBs allowed for the separation of enantiomerically pure complexes. The platinum complexes acted as pincer & pi;-alkynyl ligands for Cu(I) in the synthetic process, leading to the formation of mononuclear bis-cyclotribenzylene complexes by removing Cu+ cations with NaCN. However, these complexes failed to form metallo-cryptophanes, indicating the superiority of one pot self-assembly processes for their preparation.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Laura Koering, Nikolai A. Sitte, Markus Bursch, Stefan Grimme, Jan Paradies
Summary: The metal-free catalytic hydrogenation of secondary carboxylic acid amides is achieved through two new catalytic reactions, involving the conversion of amides into imidoyl chlorides and the subsequent hydrogenation of the generated chlorides by an FLP-catalyst. Mechanistic and quantum mechanical calculations support the unique role of chloride as a Lewis base in FLP-mediated H-2-activation during the hydrogenation process.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Andrei Gurinov, Benedikt Sieland, Andrey Kuzhelev, Hossam Elgabarty, Thomas D. Kuehne, Thomas Prisner, Jan Paradies, Marc Baldus, Konstantin L. Ivanov, Svetlana Pylaeva
Summary: A novel set of polarizing agents - mixed-valence compounds have been investigated through theoretical and experimental methods, showcasing their performance in high-field dynamic nuclear polarization (DNP) NMR experiments in the solid state. These compounds, with molecular mobility persisting even in solids, can be used to conduct Overhauser-DNP experiments in the solid state, providing favorable conditions for dynamic nuclear polarization formation at ultra-high magnetic fields.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Garrit Wicker, Roland Schoch, Jan Paradies
Summary: The borane-catalyzed synthesis of dihydroquinoline-4-ones has been developed, with high yields and excellent diastereoselectivity. The reaction mechanism is investigated through kinetic, isotope labeling, and computational experiments.
Article
Chemistry, Organic
Rundong Zhou, Jan Paradies
Summary: The borane catalyzed redox isomerization of 2-amino chalcones was successfully developed, leading to the synthesis of tetrahydroquinolines in high yields as a mixture of cis/trans diastereomers. The investigation into the reaction mechanism revealed that the reaction proceeds through a concerted [1,5] hydride shift mechanism, distinct from borane-mediated C(sp(3))-H hydride abstraction.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Laura Koering, Nikolai A. Sitte, Jan Paradies
Summary: The paper reviews the development of frustrated Lewis pair catalyzed hydrogenation of tertiary and secondary amides, as well as strategies to overcome challenges in the reaction development process. Furthermore, the chemistry is extended to the hydrogenation of polyamides and trifluoroacetamides for the introduction of trifluoroethyl groups into organic molecules.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Garrit Wicker, Rundong Zhou, Roland Schoch, Jan Paradies
Summary: The stereospecific sigmatropic carbon shift of C3 ammonium enolates has been discovered. According to mechanistic, kinetic, and computational experiments, this rearrangement proceeds via the catalytic generation of a transient C3 ammonium enolate by intramolecular aza-Michael addition. The reaction produces tetrahydroquinoline-4-ones with excellent diastereoselectivities and high yields.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Peng Hou, Sebastian Peschtrich, Nils Huber, Wolfram Feuerstein, Angela Bihlmeier, Ivo Krummenacher, Roland Schoch, Wim Klopper, Frank Breher, Jan Paradies
Summary: This study presents the synthesis and characterization of a series of quinoid sulfur-containing imidazolyl-substituted heteroacenes. The optoelectronic and magnetic properties of these compounds were investigated using various spectroscopic techniques and quantum-chemical calculations, and compared to their benzo congeners.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Applied
Benedikt Sieland, Axel Hoppe, Arne J. Stepen, Jan Paradies
Summary: A frustrated Lewis pair-catalyzed hydroboration of aromatic and aliphatic nitriles was developed, providing primary amines in high yields with low catalyst loading. The reaction exhibits high functional group tolerance and Z-selectivity.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Applied
Jakob F. Schneider, Adam Becalski, Tony Zhao, Fuqi Chen, Yifu Liao, Dorothea F. K. Rawn
Summary: 2- and 3-monochloropropanediol esters (MCPDEs) are process-induced contaminants found in vegetable oils used for food production. In this study, infant formula samples from the Canadian market were analyzed in 2015 and 2019, showing a decrease in MCPDE levels over time. The occurrence of MCPDEs in infant formula has been a concern, but the data suggests that levels have been decreasing.
FOOD ADDITIVES AND CONTAMINANTS PART A-CHEMISTRY ANALYSIS CONTROL EXPOSURE & RISK ASSESSMENT
(2022)
Article
Chemistry, Multidisciplinary
Laura Koering, Arne Stepen, Bernhard Birenheide, Simon Barth, Maxim Leskov, Roland Schoch, Felix Kraemer, Frank Breher, Jan Paradies
Summary: A series of redox-responsive ferrocenyl-substituted boranes and boronic esters were synthesized, and the oxidation of the ferrocenyl ligand to the ferrocenium increased the Lewis acidity beyond the strength of SbF5. This was investigated experimentally and computationally, and the resulting highly Lewis acidic boron compounds were used for catalytic C-F and S-F bond activation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Jakob F. Schneider, Adam Becalski, Tony Zhao, Yihui Liu, Fuqi Chen, Dorothea F. K. Rawn
Summary: Glycidyl fatty acid esters (GEs) are contaminants in vegetable oils that can release carcinogenic and genotoxic glycidol when hydrolyzed in the human body. The presence of GEs in vegetable oils used for infant formula may pose health risks for babies. A study analyzed different types of infant formula products in 2015 (35 samples) and 2019 (33 samples), finding that the concentrations of bound glycidol reached a maximum of 40.3 ng/g in 2015 samples and 31.5 ng/g in 2019 samples. However, the concentrations of bound glycidol were lower in 2019 compared to previous studies. The study also compared the GE concentrations across different manufacturers.
FOOD ADDITIVES AND CONTAMINANTS PART A-CHEMISTRY ANALYSIS CONTROL EXPOSURE & RISK ASSESSMENT
(2023)
Article
Chemistry, Multidisciplinary
Peng Hou, Sebastian Peschtrich, Wolfram Feuerstein, Roland Schoch, Stephan Hohloch, Frank Breher, Jan Paradies
Summary: The synthesis of three new imidazolyl-substituted sulfur-containing heteroacenes is presented. These heteroacenes, composed of annelated benzo- and naphthothiophenes, serve as precursors for the generation of open-shell quinoid heteroacenes through oxidation with alkaline ferric cyanide. Spectroscopic and computational experiments provide evidence for the formation of reactive open-shell quinoids, which rapidly transform into paramagnetic polymeric materials.
Article
Chemistry, Organic
Rundong Zhou, Zoleykha Pirhadi Tavandashti, Jan Paradies
Summary: In recent years, frustrated Lewis pairs have been extensively used for activating small molecules and catalytic transformations. This graphical review aims to provide a fundamental understanding of frustrated Lewis pair reactivity and its exploitation in catalytic reactions.
Review
Chemistry, Multidisciplinary
Jan Paradies
Summary: Metal-free hydrogenation through the activation of molecular hydrogen by main-group element catalysts, known as frustrated Lewis pairs, has emerged as an alternative to transition metal catalysis. However, the understanding of the structure-reactivity relationship is less developed compared to transition metal complexes. In this Account, the correlation between Lewis acidity, Lewis basicity, and reactivity is discussed, along with the systematic study of frustrated Lewis pairs in various reactions. These studies have led to the development of qualitative and quantitative structure-reactivity relationships in imine hydrogenations and the discovery of new catalytic systems for the hydrogenation of nitroolefins, acrylates, malonates, amines, aza-heterocycles, and deoxygenation of phosphane oxides and carboxylic acid amides.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Inorganic & Nuclear
Fabian A. Watt, Benedikt Sieland, Nicole Dickmann, Roland Schoch, Regine Herbst-Irmer, Holger Ott, Jan Paradies, Dirk Kuckling, Stephan Hohloch
Summary: Two rigid mesoionic carbene (MIC) ligands were synthesized via intramolecular Finkelstein cyclisation, and their coordination behavior towards nickel(s) acetate was investigated. Despite minor differences in chemical composition, the nickel(s) carbene complexes showed curious differences in chemical properties, and their potential in coupling reactions was evaluated.
DALTON TRANSACTIONS
(2021)
