Article
Chemistry, Multidisciplinary
Lenka Pallova, Laura Abella, Marion Jean, Nicolas Vanthuyne, Cecile Barthes, Laure Vendier, Jochen Autschbach, Jeanne Crassous, Stephanie Bastin, Vincent Cesar
Summary: The first efficient chiral helicene-NHC gold(I) complexes for enantioselective catalysis have been synthesized. Their structural and stereochemical characterization confirms their potential in asymmetric catalysis, demonstrated by the benchmark cycloisomerization reaction with high enantiomeric excess.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Hyunho Kim, Minseop Kim, Hayoung Song, Eunsung Lee
Summary: The synthesis of ambiphilic N-heterocyclic carbene ligand indol-2-ylidene (IdY, A) was described, along with its ambiphilicity and synthetic utility. Experimental and computational studies showed that IdY lies between CAAC-5 and CAArC, with copper complexes capable of carboboration of terminal alkynes with high regioselectivity and good yields within 30 minutes.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Yuan-Yuan Xu, Zhong-Hua Gao, Cao-Bo Li, Song Ye
Summary: The enantioselective alpha-oxidative coupling of enals with carboxylic acids was achieved by umpolung of an NHC-bound enolate with an iodine(III) reagent. The reaction produced alpha-acyloxyl-beta,gamma-unsaturated esters in good yields, with high regio- and enantioselectivities. The reaction involved the formation of an enol iodine(III) intermediate from the enolate with iodosobenzene, which changed the polarity of the enal's alpha-carbon from nucleophilic to electrophilic and facilitated the subsequent carboxylate addition.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Zi-Jing Zhang, Yu-Hua Wen, Jin Song, Liu-Zhu Gong
Summary: The study developed an efficient KR and DyKAT method using N-heterocyclic carbene (NHC)/copper cooperative catalysis, resulting in highly enantioenriched derivatives and products with high structural diversity. Mechanistic studies indicated that NHC can regulate the catalytic activity of the copper catalyst, enabling the switch of chemical selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Bastiaan Kooij, Zhaowen Dong, Paul Varava, Farzaneh Fadaei-Tirani, Rosario Scopelliti, Laura Piveteau, Kay Severin
Summary: This study reports the preparation and structural characterization of vanadium complexes with N-heterocyclic vinylidene ligands, enabled by utilizing diazoolefins as ligand precursors. Structural and theoretical analysis show that N-heterocyclic vinylidenes can act as strong 6e(-) donor ligands, forming strong metal-carbon interactions.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Zhi-Zhou Pan, Jia-Heng Li, Hu Tian, Liang Yin
Summary: A copper(I)-catalyzed asymmetric allylation of ketones with 2-aza-1,4-dienes has been demonstrated, providing a series of functionalized homoallyl tertiary alcohols with high to excellent enantioselectivity. The deprotonation of N-allyl-1,1-diphenylmethanimines is the rate-determining step in the reaction, generating nucleophilic allyl copper(I) species. The utility of this method has been demonstrated by the asymmetric synthesis of (R)-boivinianin A and (R)-gossonorol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Jian-Hua Liu, Qing Zhou, Yao Lin, Zhu-Lian Wu, Tian Cai, Wei Wen, Yan-Min Huang, Qi-Xiang Guo
Summary: In this study, a highly efficient atom-economic asymmetric alpha-allylation method using chiral-aldehyde/palladium catalyst was reported. This method enables the asymmetric alpha-allylation of different 1,3-dienes and allenes with N-unprotected amino acid esters, leading to the synthesis of alpha,alpha-disubstituted chiral alpha-amino acid esters with high efficiency, good yields, and stereoselectivities. No N-allylation byproducts were observed in these reactions. Two reaction models were proposed based on mechanistic control experiments. Overall, this work demonstrates a new approach for preparing structurally diverse chiral amino acids and provides insights for developing chiral-aldehyde catalytic systems.
Article
Chemistry, Multidisciplinary
Si-Qing Wang, Zong-Ci Liu, Wen-Jun Yue, Liang Yin
Summary: This study reveals a vinylogous aldol-type reaction for the synthesis of chiral gamma-hydroxyl-alpha,beta-unsaturated azaarenes with high selectivity and yields. The use of different ligands can control the formation of the carbon-carbon double bond in the products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Wacharee Harnying, Panyapon Sudkaow, Animesh Biswas, Albrecht Berkessel
Summary: Simple carboxylic acids, like benzoic acid, have been found to enhance the activity of N-heterocyclic carbene (NHC) catalysts in the oxidative esterification of aldehydes. A protocol using a novel N-Mes-/N-2,4,6-trichlorophenyl 1,2,4-triazolium salt as catalyst and benzoic acid as co-catalyst was developed for the transformation of a wide range of sterically hindered alpha- and beta-substituted aliphatic aldehydes/enals. The observed effect is believed to be due to the carboxylic acid-induced acceleration of acyl transfer from azolium enolate intermediates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ming-Yao Huang, Yu-Tao Zhao, Cheng-Da Zhang, Shou-Fei Zhu
Summary: This study reports a highly selective method for the B-H bond insertion reactions of alpha-silylcarbenes generated from 1-silylcyclopropenes using a chiral copper(I)/bisoxazoline catalyst. The method allows for the construction of chiral gamma,gamma-disubstituted allylic gem-silylboranes, which cannot be prepared using any other known methods. The newly developed products are versatile allylic bimetallic reagents with high stability and great synthetic potential for the construction of complex molecules with continuous chiral centers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Wu Yuzhu, Shen Panpan, Duan Wenzeng, Ma Yudao
Summary: The first carbene-catalyzed enantioselective 1,6-conjugate addition of boron to para-quinone methides was achieved using a commercially available chiral triazolium and bis(pinacolato)diboron. This reaction features mild conditions, broad substrate scope, excellent functional group tolerance, and good yield and enantioselectivity. Remarkably, even in the absence of any transition metals, the reaction proceeded well with just 0.1 mol% of catalyst loading without significant loss of yield and enantioselectivity, although longer reaction time was required.
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Jin Zhang, Xue Li, Tao Li, Gaopeng Zhang, Kerou Wan, Yangmin Ma, Ran Fang, Roman Szostak, Michal Szostak
Summary: This article presents the research on activation reactions using boryl-copper in organic synthesis and catalysis, with a focus on the development and application of Cu(I)-thiazol-2-ylidenes.
Article
Chemistry, Multidisciplinary
Soumen Barik, Sayan Shee, Soumik Das, Rajesh G. Gonnade, Garima Jindal, Subrata Mukherjee, Akkattu T. Biju
Summary: This study describes the atroposelective synthesis of N-aryl succinimides with axially chiral C-N bonds catalyzed by N-heterocyclic carbenes, achieving good yields and ee values. Preliminary investigations were also conducted on the rotation barrier for the C-N bond, temperature dependence, and detailed DFT studies on the mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Zeyu Han, Derek P. Gates
Summary: This study discovered a high-yielding P=C bond metathesis of phosphaalkenes catalyzed by N-heterocyclic carbenes, resulting in cyclic oligomers formally derived from ArP=PAr. Preliminary mechanistic studies revealed NHC=PAr as key phosphinidene transfer agents, and novel cyclic intermediates were observed. This work represents a rare application of non-metal-based catalysts for transformations involving main-group elements.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Sofie M. P. Vanden Broeck, Catherine S. J. Cazin
Summary: This review focuses on manganese complexes bearing N-heterocyclic carbene (NHC) ligands. The complexes exhibit different properties in various oxidation states and are widely used in catalytic reactions, particularly in CO2 reduction, hydrosilylation and alkylation.
Article
Chemistry, Organic
Arnaud Osi, Nikolay Tumanov, Johan Wouters, Aurelien Chardon, Guillaume Berionni
Summary: A new boratriptycene derivative with a selenium atom in the bridgehead position of the triptycene scaffold was synthesized, and its Lewis acidity was evaluated experimentally and computationally. The introduction of a selenium atom allows precise modification of the pyramidalization of the boron atom environment, affecting the Lewis acidity parameters of the triarylborane.
SYNTHESIS-STUTTGART
(2023)
Article
Engineering, Environmental
Roman Lyubimenko, Andrey Turshatov, Alexander Welle, Peter G. Weidler, Bryce S. Richards, Andrea I. Scha
Summary: The application of poly (vinylidene-fluoride) membranes can enhance the photocatalytic degradation of micropollutants, but light propagation and pollutant concentration remain limiting factors.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Organic
Laurie Bodart, Johan Wouters
Summary: This study presents useful descriptors for discriminating structures with selenium-containing chalcogen bonds. The most relevant parameters for identifying conventional chalcogen bonds are the C-Se angle and the distance between X and the C-Se-C plane, while for chalcogen...pi bonds, the relevant parameters are the C-Se angle and the angle between the C-Se bond and the normal to the aromatic ring plane.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Organic
Michela Maria Marchese, Sebastian Strahler, Lucian Ghiba, Olivier Riant
Summary: In this study, we developed a one-pot, copper-catalyzed aminodifluoroalkylation of enylaniline derivatives. This approach enables the catalytic construction of a wide range of pyrrolidines and piperidines substituted with a gem-difluoro moiety.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Benon P. Maliszewski, Tahani A. C. A. Bayrakdar, Perrine Lambert, Lama Hamdouna, Xavier Trivelli, Luigi Cavallo, Albert Poater, Marek Belis, Olivier Lafon, Kristof Van Hecke, Dominic Ormerod, Catherine S. J. Cazin, Fady Nahra, Steven P. Nolan
Summary: In this study, the catalytic activity of a series of platinum(II) pre-catalysts with N-heterocyclic carbene (NHC) ligands in the alkene hydrosilylation reaction is reported. The structural and electronic properties of these catalysts are fully characterized using X-ray diffraction analysis and nuclear magnetic resonance spectroscopy (NMR). A structure-activity relationship within this group of pre-catalysts is established, and mechanistic insights into the catalyst activation step are provided. One of the complexes shows exceptional catalytic performance, achieving a turnover number (TON) of 970,000 and a turnover frequency (TOF) of 40,417 h(-1) at 1 ppm catalyst loading. Furthermore, a solvent-free and open-to-air alkene hydrosilylation protocol with efficient platinum removal (reducing residual Pt from 582 ppm to 5.8 ppm) is disclosed.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Applied
Mourad Boukachabia, Hacene Bendjeffal, Mounia Merabet Khelassi, Olivier Riant
Summary: A statistical approach was used to optimize the acylation of l-menthol using natural kaolin as a catalyst. The main operational parameters, such as solvent volume, acyl donor amount, temperature, and catalytic rate of kaolin, were studied. The results showed that temperature, acyl donor/acceptor ratio, kaolin mass, and solvent volume were significant factors affecting the acylation process. Optimal reaction conditions were determined and validated experimentally, achieving complete conversion after 30 minutes. The environmentally friendly process was also applied to other monoterpenic alcohols, yielding acetates with 45%-90% yield.
FLAVOUR AND FRAGRANCE JOURNAL
(2023)
Article
Chemistry, Physical
Joana M. Ribeiro, Frederico J. Rodrigues, Filipe C. Correia, Inga Pudza, Alexei Kuzmin, Aleksandr Kalinko, Edmund Welter, Nuno P. Barradas, Eduardo Alves, Alec P. LaGrow, Oleksandr Bondarchuk, Alexander Welle, Ahmad Telfah, Carlos J. Tavares
Summary: Transparent ZnO:Sb thin films were deposited using magnetron sputtering, and their structure and disorder were studied. It was found that Sb doping influenced the crystalline structure and promoted partial amorphization. A film with 12 at% of Sb exhibited the highest Seebeck coefficient and thermoelectric power factor.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Nathalie Body, Corentin Lefebvre, Pierre Eloy, Tommy Haynes, Sophie Hermans, Olivier Riant
Summary: The impact of silica nanoparticles morphology on the photooxidation of citronellol was investigated. It was found that the core-shell structure of silica nanoparticles exhibited the best activity, recyclability, and dye immobilization rate.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Ilona Wagner, Simon Spiegel, Julian Brueckel, Matthias Schwotzer, Alexander Welle, Martina H. H. Stenzel, Stefan Braese, Salma Begum, Manuel Tsotsalas
Summary: Surface engineering of MOF NPs using dynamic modification strategies enables the tailoring of PEG-grafted MOF NPs with improved colloidal stability and high dispersity, while maintaining their morphology and lattice crystallinity. The PEG-grafted MOF NPs show reduced adsorption of HSA protein compared to uncoated ones, indicating the potential for reducing nonspecific interactions and introducing targeting moieties for specific interactions. This approach expands the applications of colloidal MOF NPs in biologically relevant fields.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Article
Biochemistry & Molecular Biology
Zeinab Mohamed Hassan, Wei Guo, Alexander Welle, Robert Oestreich, Christoph Janiak, Engelbert Redel
Summary: Gas-phase infiltration of the carbonylchloridogold(I), Au(CO)Cl precursor into the pores of HKUST-1 SURMOFs leads to the formation of ordered gold nanoclusters within the MOF matrix. These nanoclusters are homogeneous and distributed in the medium-sized pores of HKUST-1. The characterization of Au-x@HKUST-1 was performed using various techniques including SEM, IRRA, Raman spectroscopy, ToF-SIMS, XPS, and ICP-OES.
Article
Chemistry, Multidisciplinary
Laurie Bodart, Jeanne Body, Nikolay Tumanov, Tom Leyssens, Johan Wouters
Summary: This study identifies and characterizes four new solid forms of pyrimethamine and sulfathiazole, including a cocrystal and solvated salt cocrystals. The desolvation of the salt cocrystals leads to the formation of stable mixtures. Additionally, both the pyrimethamine-sulfathiazole cocrystal and solvated salt cocrystal show an increase in drug solubility.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Pharmacology & Pharmacy
Alexander Welle, Mohit Mehta, Karin Marek, Harry Peters, Peter Van der Wel, Olukayode Imole
Summary: This study investigated the impact of high shear blending conditions on the distribution of magnesium stearate on lactose particles. The results showed that magnesium stearate significantly affected the rheological properties of the blends, and blending speed had a strong influence on the distribution of magnesium stearate on lactose surface, while blending time had a minor effect.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2023)
Article
Materials Science, Multidisciplinary
R. M. Jentner, S. P. Tsai, A. Welle, S. Scholl, K. Srivastava, J. P. Best, C. Kirchlechner, G. Dehm
Summary: Differentiation between granular bainite and polygonal ferrite in HSLA steels is challenging due to their similar mechanical and chemical properties. In this study, the kernel average misorientation from EBSD was used to classify and quantify the microstructural constituents. ECCI validation was performed to investigate the effect of grain tolerance angle on classification. The results showed that the automated EBSD classification approach based on local misorientation achieved reliable results with a grain tolerance angle of 5°.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Chemistry, Physical
Denis Chusov, Gary A. A. Molander, Virginie Ratovelomanana-Vidal, Olivier Riant, Emmanuelle Schulz
Summary: In this paper, we discuss the extensive scholarly contributions of Professor Henri B. Kagan, our mentor and colleague, and the significant impact of his research on various fields of chemistry, including asymmetric oxidation, asymmetric reduction, unique features in lanthanide chemistry, issues of nonlinear effects, and the question of the origin of chirality on earth.
Article
Chemistry, Multidisciplinary
Benon Maliszewski, Eleonora Casillo, Perrine Lambert, Fady Nahra, Catherine Cazin, Steven Nolan
Summary: This article reports an efficient olefin hydrosilylation protocol using Pt(ii)-thioether-based pre-catalysts. These simple and readily available complexes exhibit excellent catalytic performance and offer significant advantages over existing alternatives, enabling rapid and high conversions at ppm-level catalyst loadings.
CHEMICAL COMMUNICATIONS
(2023)
