Review
Chemistry, Multidisciplinary
Fabian Schmidt, Mirza Cokoja
Summary: The paper presents an overview of supramolecular strategies for the epoxidation of hydrophobic olefins in water using phase transfer-controlling surfactants, with a focus on the rationale of phase transfer and the efficiency of catalyst recycling. The catalyst can be transferred to both the aqueous and organic phase depending on the surfactant type and reaction requirements. The comparison between these two concepts considers phase transfer type, supramolecular interactions between catalyst and surfactant, catalyst activity, and the potential for efficient and environmentally friendly catalyst recycling.
Article
Multidisciplinary Sciences
John M. Ovian, Petra Vojackova, Eric N. Jacobsen
Summary: Asymmetric transition-metal catalysis is a powerful strategy for producing enantiomerically enriched molecules. The traditional strategy for inducing enantioselectivity involves using chiral ligands to create a reactive metal site that promotes the formation of the major enantiomer and inhibits the formation of the minor enantiomer. However, this approach has limitations in certain scenarios. This study introduces a new approach that utilizes neutral hydrogen-bond donors to achieve enantioselectivity through ion pairing and non-covalent interactions. The results demonstrate high enantioselectivity in intramolecular ruthenium-catalyzed propargylic substitution reactions.
Article
Chemistry, Physical
Zhe An, Yuanzhong Tang, Yitao Jiang, Hongbo Han, Qi Ping, Wenlong Wang, Yanru Zhu, Hongyan Song, Xin Shu, Xu Xiang, Jing He
Summary: By utilizing nanosheets of layered double hydroxides (LDHs) to modify α-amino acid derivatives as chiral ligands, an efficient strategy has been proposed to promote the enantioselectivity of Mn(III)-catalyzed indene epoxidation, achieving an enantioselectivity of more than 91.0%.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Matthew J. J. Genzink, Matthew D. D. Rossler, Herman Recendiz, Tehshik P. P. Yoon
Summary: Chiral acid catalysts are shown to promote highly selective visible-light photocycloadditions, leading to the synthesis of truxinate natural products. This general approach allows for the efficient synthesis of dimeric and pseudodimeric cyclobutane natural products with excellent enantioselectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Yibing Liu, Liqun Hu, Yuzhu Zheng, Xiong Fang, Youwei Xie
Summary: This publication describes the use of Re2O7 in HFIP to activate inert and electronically deactivated olefins for a challenging intramolecular hydroacyloxylation reaction. Both HFIP and an internal carboxy group are crucial for the successful implementation of this transformation, as they assist in the formation and stabilization of the key cationic intermediate through hydrogen-bonding interactions with ReO4-.
Article
Chemistry, Inorganic & Nuclear
Wenyan Ma, Yida Zhou, Jiani Zhang, Siyu Zong, Bolun Wang, Jiyang Li
Summary: This study proposes a method to transform waste zeolite catalyst into carbon dots-zeolite composites with controllable luminescence. By adjusting the calcination conditions, the fluorescence behavior of the composites can be tuned. This work provides a novel synthetic route for recycling waste materials.
INORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Han Wang, Yan Zhao, Dong Zhang, Yucai Li, Yingnan Dong, Shuaijie Wang, Shiwei Song, Jian Wang, Gang Wang
Summary: A novel compound based on catalytic functional metal rhenium, pyridinium perrhenate (PyHReO4), was synthesized and characterized. The compound was used as a catalyst in two types of reactions, the epoxidation of cyclooctene and the Baeyer-Villiger oxidation of cyclic ketones. The effects of various factors on the reactions were investigated, and the optimum reaction conditions of the catalyst system were determined. Both catalytic reactions showed high yields and selectivity.
JOURNAL OF CHEMICAL SCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Alexandra Walter, Wolfgang Eisenreich, Golo Storch
Summary: This study reports a photochemical approach using flavin catalysts to oxidize silyl enol ethers to α,β-unsaturated ketones. The catalysts exhibit good stability throughout the reaction and can be successfully applied in subsequent aerobic epoxidation reactions. The sequential catalytic activity of flavin enables rapid diversification of substrates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Isaiah O. Betinol, Yutao Kuang, Jolene P. Reid
Summary: This article discusses how statistical models can be used to guide the selection of efficient synthetic routes to obtain a target molecule, and introduces the accuracy of this method in distinguishing catalysts and reactions.
Article
Chemistry, Applied
M. A. Salaev, A. A. Salaeva, O. V. Vodyankina
Summary: The study demonstrates that Cs, Re, and Cl promoters can enhance the performance of silver catalysts in ethylene epoxidation by adjusting the substrate location, electronic density distribution, and substrate binding strength to optimize the reaction.
Article
Chemistry, Physical
Eric D. Hernandez, Babgen Manookian, Scott M. Auerbach, Friederike C. Jentoft
Summary: Alkylcyclopentenyl cations play a significant role in catalytic reactions, contributing to the formation of olefins and aromatics. Research utilizing techniques such as IR spectroscopy, UV-vis spectroscopy, and density functional theory has provided insights into the structure and formation mechanisms of these cations.
Article
Chemistry, Physical
Rasool Babaahmadi, Mona Jalali, Jason A. Smith, Brian F. Yates, Alireza Ariafard
Summary: It was found that in catalytic reactions, the activation of organic Lewis bases by bismuth(III) salts requires the involvement of a p orbital of bismuth.
Article
Chemistry, Physical
Kosuke Yamaguchi, Yoshinao Nakagawa, Congcong Li, Mizuho Yabushita, Keiichi Tomishige
Summary: The removal of vicinal diols through deoxydehydration and hydrogenation reactions using a mixture catalyst of ReOx/CeO2 and CeO2-supported base metals has been studied as an alternative to the expensive Pd-based catalysts. The mixture catalyst showed high activity and selectivity similar to that of Pd-based catalysts, and could be applied to various diols and polyols. However, the activity of the mixture catalyst decreased during reuse.
Article
Chemistry, Applied
Gabriele Grieco, Olivier Blacque
Summary: The reduction of several aromatic nitro compounds to amines using two novel catalytic systems under microwave irradiation showed higher TON and TOF compared to previous systems, but with a narrower reaction scope.
APPLIED ORGANOMETALLIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Miriam Calabrese, Andrea Pizzi, Andrea Daolio, Antonio Frontera, Giuseppe Resnati
Summary: MTO is a widely used catalyst for metathesis, olefination, and oxidation reactions. The occurrence of sigma-hole interactions in catalytic systems extends to MTO, and the optimization of the ligand-acceleration effect of pyridine can enhance the catalytic efficiency of olefin epoxidation under MTO catalysis.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Organic
Guangxing Pan, Shaoheng Qin, Dawen Xu, Fritz E. Kuehn, Hao Guo
Summary: The photoinduced pericyclic cascade reaction described in this study provides a novel approach to oxabicyclo[4.2.0]octenes, involving [2 + 2]-photocycloaddition, base-promoted elimination, retro-4p-electrocyclization, [1,5]-H shift, and 4p-electrocyclization processes. This reaction exhibits broad substrate scope, good functional group tolerance, and excellent diastereoselectivity.
Article
Chemistry, Multidisciplinary
Bo Zhang, Tenglong Guo, Yuxuan Liu, Fritz E. Kuhn, Chao Wang, Zongbao K. Zhao, Jianliang Xiao, Changzhi Li, Tao Zhang
Summary: The study presents a new strategy for the direct transformation of lignin model compounds into benzylamines and phenols, with experimental data indicating the significance of dehydrogenation reaction and the role of secondary amines in the transformation. This work provides a novel opportunity for sustainable synthesis of benzylamines from renewable biomass, expanding the products pool of biomass conversion for future biorefinery demands.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Eva-Maria H. J. Esslinger, Jonas F. Schlagintweit, Greta G. Zambo, Alexander M. Imhof, Robert M. Reich, Fritz E. Kuehn
Summary: The performance of trans axially substituted mono-(2 a) and bis(tert-butylisocyanide) (2 b) complexes derived from the highly active bio-inspired iron(II) catalyst in homogenous olefin epoxidation catalysis is reported. The use of H2O2 as oxidant in combination with the Lewis acid Sc(OTf)(3) as additive significantly improves catalytic activity. Despite the introduction of pi-accepting isocyanide ligands not enhancing catalytic performance, both compounds exhibit a unique high-temperature tolerance compared to other iron NHC epoxidation catalysts.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Greta G. Zambo, Jonas F. Schlagintweit, Robert M. Reich, Fritz E. Kuehn
Summary: The development of selective oxidation processes for hydrocarbons is an important area of research in catalysis. Making these processes environmentally friendly is a challenge. N-heterocyclic carbenes (NHCs) have attracted attention for their ability to stabilize transition metals in high oxidation states, which are key intermediates in oxidation catalysis. This review summarizes recent applications of 3d transition metal NHC complexes in oxidation catalysis and highlights advances in catalytic oxidation of important substrates such as alkenes, alkanes, aromatics, alcohols, and amines until the end of 2021. It also discusses the activation of molecular oxygen using first row transition metal NHC complexes as a green and abundant oxidant.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Yangming Ding, Tenglong Guo, Zhewei Li, Bo Zhang, Fritz E. Kuhn, Chang Liu, Jian Zhang, Dezhu Xu, Ming Lei, Tao Zhang, Changzhi Li
Summary: A one-pot cascade reaction was developed for the synthesis of quinoline from beta-O-4 model compounds, achieving high yields. The reaction pathway involves selective cleavage of C-O bonds, dehydrogenation, aldol condensation, and C-N bond formation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Bo Zhang, Tenglong Guo, Zhewei Li, Fritz E. Kuhn, Ming Lei, Zongbao K. Zhao, Jianliang Xiao, Jian Zhang, Dezhu Xu, Tao Zhang, Changzhi Li
Summary: This study reports a novel method for synthesizing heterocyclic aromatic compounds from lignin, which is of great importance for expanding the product portfolio derived from biomass. The method is transition-metal free and sustainable, making it applicable for pharmaceutical synthesis.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Mohammad Kaikhosravi, Alexander D. Boeth, Michael J. Sauer, Robert M. Reich, Fritz E. Kuehn
Summary: The heterobimetallic N-heterocyclic dicarbene (NHDC) rhodium ruthenium complex was synthesized via transmetallation and tested as a catalyst in the transfer hydrogenation reaction of acetophenone. The complex exhibited high turnover frequency and good catalytic performance.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2022)
Editorial Material
Chemistry, Applied
Bo Zhang, Fritz E. Kuehn
JOURNAL OF ENERGY CHEMISTRY
(2023)
Article
Chemistry, Physical
Tim P. Schlachta, Greta G. Zambo, Michael J. Sauer, Isabelle Rueter, Carla A. Hoefer, Serhiy Demeshko, Franc Meyer, Fritz E. Kuehn
Summary: A comparative study was conducted to investigate the influence of electronic variations on the catalytic performance of three iron(II) NHC epoxidation catalysts. Different ligands were used to prepare the complexes, which were characterized using various methods. The results showed that a lower electron density at the iron atom led to a decline in epoxidation activity, while a more electron rich iron center did not necessarily result in higher activity due to reduced catalyst stability. Addition of Lewis acids significantly improved both activity and stability of the catalysts.
JOURNAL OF CATALYSIS
(2023)
Review
Chemistry, Multidisciplinary
Tim P. P. Schlachta, Fritz E. E. Kuehn
Summary: Cyclic iron tetracarbenes are a class of macrocyclic iron N-heterocyclic carbene (NHC) complexes, inspired by heme analogs but with different electronic properties. The modification of their ligand framework allows control over the structural and electronic properties of the complexes. These iron tetracarbene complexes exhibit unique reactivity, involving the isolation of uncommon iron(iii) and iron(iv) species. They have been successfully applied in various catalytic reactions, such as C-H activation, CO2 reduction, aziridination, and epoxidation. This review provides insights for researchers to evaluate the properties of their complexes and optimize catalyst properties through ligand design.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Inorganic & Nuclear
Greta G. Zambo, Johannes Mayr, Michael J. Sauer, Tim P. Schlachta, Robert M. Reich, Fritz E. Kuehn
Summary: The synthesis and characterization of a novel macrocyclic and abnormally coordinating, mesoionic N-heterocyclic carbene iron complex are reported. The complex exhibits strong sigma-donor ability of the carbene moieties, indicating efficient catalytic activity in oxidation reactions. Initial tests on the epoxidation of cis-cyclooctene validate the assumption.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Alexander D. Boeth, Michael J. Sauer, Walter Baratta, Fritz E. Kuehn
Summary: The bis-abnormal N-heterocyclic carbene (aNHC) ruthenium complexes showed high catalytic activity in transfer hydrogenation and Oppenauer-type oxidation reactions. The order of reactivity was found to be influenced by steric effects.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Review
Materials Science, Multidisciplinary
Ghada Bassioni, Reham Farid, Mayar Mohamed, Rawia M. Hammouda, Fritz E. Kuehn
Summary: The review discusses methods for synthesizing magnesium oxide and magnesium hydroxide, as well as their applications, providing information on the hydration process and influencing factors.
MATERIALS ADVANCES
(2021)
Article
Chemistry, Multidisciplinary
Tim P. Schlachta, Markus R. Anneser, Jonas F. Schlagintweit, Christian H. G. Jakob, Carolin Hintermeier, Alexander D. Boeth, Stefan Haslinger, Robert M. Reich, Fritz E. Kuehn
Summary: The first diiron(iii,iv)-mu(2)-oxo tetracarbene complex was isolated and characterized using various methods, showing the presence of a transient high-valent diiron(iv)-mu(2)-oxo species. Its formation and decay processes were investigated through UV/Vis kinetics and NMR analysis.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Jonas F. Schlagintweit, Christian H. G. Jakob, Kevin Meighen-Berger, Thomas F. Gronauer, Angela Weigert Munoz, Vanessa Weiss, Matthias J. Feige, Stephan A. Sieber, Joao D. G. Correia, Fritz E. Kuehn
Summary: Fluorescent Pd(II) and Pt(II) complexes with 4-methylene-7-methoxycoumarin (MMC) and 2,6-diisopropylphenyl (Dipp) substituted NHC/1,2,3-triazole hybrid ligands were described, showing antiproliferative activity against cervix and breast cancer cells, with the tetradentate coordination mode being notably more effective. The Pd(s) complex with bidentate coordination mode was only active against HeLa, exhibiting high selectivity for cancer cells compared to healthy skin cells. The compound is believed to be located in late endosomes or lysosomes according to fluorescence microscopy.
DALTON TRANSACTIONS
(2021)
