Article
Chemistry, Multidisciplinary
Clement Ghiazza, Lucas Wagner, Sergio Fernandez, Markus Leutzsch, Josep Cornella
Summary: Among the tools available to chemists for drug design of bioactive compounds, the bioisosteric replacement of atoms or groups of atoms is the cornerstone of modern strategies. The enzymatic deaminative hydroxylation remains unmatched despite the interest in amino-to-hydroxyl interchange. The study reports a safe and user-friendly procedure using a pyrylium tetrafluoroborate salt to selectively convert aminoheterocycles to hydroxylated analogues. Mechanistic experiments revealed an unusual mechanism for this aromatic substitution.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Gonzalo Vera, Reynald Mangeant, Silvia Stiebing, Yohann Berhault, Frederic Fabis, Thomas Cailly, Valerie Collot
Summary: A site-selective and thiol-free thiofunctionalization of electron-rich heteroarenes was reported in this study. By conducting a selective ortho-magnesiation and using S-8, direct access to S-alkyl or -aryl derivatives was achieved, followed by in situ oxidation to provide sulfoxide and sulfone derivatives. Using this protocol, Cerlapirdine was synthesized in 4 steps with an overall yield of 28%.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Alexander Kremsmair, Andreas Hess, Benjamin Heinz, Paul Knochel
Summary: Mixed TMP-bases are excellent reagents for the metalation of functionalized aromatics and heterocycles. By combining with Lewis acids, the metalation scope can be increased, and regioselectivity switches can be achieved. Highly reactive lithium bases are also compatible with various Lewis acids, and performing metalations in continuous flow using commercial setups allows for practical and convenient reaction conditions.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Clement Ghiazza, Teresa Faber, Alejandro Gomez-Palomino, Josep Cornella
Summary: This methodology presents a simple and efficient way to selectively modify heteroatom-containing aromatic structures by converting C(sp(2))-NH2 into C(sp(2))-Cl bonds. It offers wide functional group tolerance and substrate scope, allowing the modification of various heteroaromatic motifs. Additionally, it enables practitioners to apply transformations without the need for explosive diazonium salts or stoichiometric transition metals.
Article
Chemistry, Physical
Sung Joo Kim, Jae Yeol Park, Yoonsu Shim, Donghee Chang, Joon Ha Chang, Kyun Seong Dae, Jong Min Yuk
Summary: In this study, the magnesiation mechanism of Sn nanoparticles was demonstrated using liquid-phase electron microscopy. It was found that the diffusion of Mg ions into Sn is slow and involves the formation of an intermediate metastable phase and an equilibrium phase. The large stress at the interface between Sn and MgxSn leads to the formation of amorphous Mg2+xSn with overinsertion of Mg2+. The formation of Mg(OH)2 on MgxSn impedes the insertion of Mg2+ into Sn, resulting in rapid capacity fading of a Mg-Sn cell.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Organic
Min-Sung Ko, Jung-Ho Hong, Adil S. Aslam, P. Sankara Rao, Pradeep P. Desale, Jonghoon Choi, Yunho Lee, Dong-Gyu Cho
Summary: o-Arene-connected porphyrinoids were synthesized using o-(2-thienyl)vinylarene motif as a new building block. This motif can replace meso-aryl-substituted dipyrromethene and control the connectivity of porphyrinoids. The experimental results showed that the rigidified Pd-6a had higher aromaticity than 6b.
Article
Engineering, Environmental
Jie Cheng, Hong-Yi Li, Dong Hai, Xin-Mian Chen, Jiang Diao, Bing Xie
Summary: In order to minimize the toxicity of vanadium extraction tailings, the vanadium extraction efficiency should be as high as possible. This study explores the kinetics of a novel magnesiation roasting technique for vanadium slag, revealing the microscopic mechanism and proposing macroscopic kinetic models. The intensified roasting kinetics achieved a vanadium extraction efficiency of 96.65%, providing guidelines for the industrial application of this technique.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Electrochemistry
Danmei Gao, Jingren Dong, Yuan Yuan, Renchao Xiao, Yuping Liu, Danmei Yu, Changguo Chen, Aitao Tang, Dingfei Zhang, Fusheng Pan
Summary: VOCl is a promising electrode material for rechargeable batteries with good energy storage and ion diffusion properties. The discharge plateaus and conversion reaction were observed during the processes of lithiation and magnesiation. VOCl exhibits high-rate capability as a cathode material for lithium-ion batteries and has the potential to improve the performance of magnesium rechargeable batteries.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Takuya Hatakeyama, Hongyi Li, Norihiko L. Okamoto, Kohei Shimokawa, Tomoya Kawaguchi, Hiroshi Tanimura, Susumu Imashuku, Maximilian Fichtner, Tetsu Ichitsubo
Summary: The study revealed that under conditions where the magnesium migration kinetics are sufficiently enhanced, MnO2 polymorphs can transform into Mg-including spinels and then rocksalt-like phases. Alpha-MnO2 was found to exhibit reversible magnesium intercalation at 150 degrees C, while lambda-MnO2 phase possessing spinel/rocksalt structure framework is thermally unstable.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Organic
Nicholas A. Clanton, Nicolas A. Wilson, Eliezer Ortiz, Shawn T. Blumberg, Doug E. Frantz
Summary: This study describes the site-selective functionalization of unactivated allylic C-H bonds via direct deprotonation using KTMP. It demonstrates the conversion of amorphadiene to artemisinic alcohol through a simple and highly regioselective deprotonation over four other possible allylic sites, with further extrapolation to the first large-scale chemical synthesis of artemisinic acid from amorphadiene. Additionally, it highlights the successful application of this method for site-selective functionalization of unactivated allylic C-H bonds in other terpene-based natural products.
Article
Chemistry, Multidisciplinary
Carlos Corral Suarez, Ignacio Colomer
Summary: This study presents a method for trifluoromethylarylation of alkenes using anilines, without the need for additives, transition metals, photocatalysts, or excess reagents. The key role of hexafluoroisopropanol (HFIP) as a unique solvent, which establishes a hydrogen bonding network with aniline and trifluoromethyl reagent, is revealed through a detailed mechanistic study. This work unlocks the use of anilines in the selective trifluoromethylarylation of olefins via a mild protocol that avoids transition metals, expensive photocatalysts, and additives.
Article
Nanoscience & Nanotechnology
Donghan Youn, Nam Gyu Kim, Won Joon Jeong, Dong Jae Chung, Ji Young Kim, Hansu Kim
Summary: In this study, magnesiation of SiO using MgH2 was employed to enhance the initial Coulombic efficiency of SiO-based anode materials for lithium-ion batteries. The experimental results showed that magnesiation using MgH2 significantly improved the initial Coulombic efficiency, as well as the long-term cycle performance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Narges Abdolhossein Rejali, Mohammad Dinari, Yong Wang
Summary: Covalent organic frameworks (COFs) are porous and crystalline organic polymers that can be tailored by introducing diverse functionalities. However, sometimes these functionalities are not compatible with reaction conditions or interfere with other monomers. To overcome these challenges, post-synthetic modification (PSM) approaches are helpful in adjusting the porous size and improving stability without affecting crystallite. Different PSM strategies, including post-functionalization, post-metalation, chemical locking, and host-guest post-modification, have been discussed in this review. The potential applications of post-modified COFs in various fields, such as energy storage and conversion, heterogeneous catalysts, food safety evaluation, gas separation, environmental domains, and biological applications, have also been explored.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Narges Abdolhossein Rejali, Mohammad Dinari, Yong Wang
Summary: Covalent organic frameworks (COFs) are porous and crystalline organic polymers that have found diverse applications in various fields. Post-synthetic modification (PSM) strategies, including post-functionalization, post-metalation, chemical locking, and host-guest post-modifications, offer a helpful approach to introduce functionalities into COFs. These modifications allow for tunable porous size, improved stability, and modification of features such as conductivity, hydrophobicity/hydrophilicity, and chirality. The potential applications of post-modified COFs include energy storage and conversion, heterogeneous catalysis, food safety evaluation, gas separation, environmental remediation, and biological applications.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Shiqi Chen, Si Cao, Chaoyang Liu, Baoxu Wang, Xiaorui Ren, Hang Huang, Zhihong Peng, Xi Wang
Summary: The study presents a transition metal/ligand-free disulfuration of anilines with disulfur transfer reagents, resembling a reductive disulfuration variation of the Sandmeyer reaction. The method shows a wide scope across aniline substrate and disulfur transfer reagent classes, enabling successful gram-scale synthesis of disulfides.
Review
Chemistry, Organic
Baosheng Wei, Paul Knochel
Summary: Cross-couplings involving organozinc reagents can proceed well in the absence of transition-metal catalysts with reactive electrophiles. Highly diastereoselective and enantioselective cross-couplings can be readily performed with room-temperature configurationally stable alkylzinc species, producing diastereoselectively and enantiomerically enriched products. Highly regioselective magnesiations of functionalized arenes and heteroarenes undergo Negishi or Cu-catalyzed cross-couplings.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Alisa S. Sunagatullina, Ferdinand H. Lutter, Paul Knochel
Summary: In this study, various dialkylmagnesiums were synthesized by reacting primary or secondary alkyl iodides with sBu(2)Mg, and these reagents underwent diverse reactions with different compounds to yield stereodefined products. Mechanistic studies revealed that these reactions proceed via a radical pathway.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
A. Hess, H. C. Guelen, N. Alandini, A. Mourati, Y. C. Guersoy, P. Knochel
Summary: This study presents a novel method for the selective ortho, ortho'-functionalization of readily available aryl oxazolines using sBu(2)Mg in toluene followed by trapping reactions with electrophiles. The conversions of these nitriles to valuable heterocycles are reported, and a tentative mechanism is proposed for the reactions.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Benjamin Heinz, Dimitrije Djukanovic, Fiona Siemens, Mohamed Idriess, Benjamin Martin, Paul Knochel
Summary: The treatment of 3-halopyridines with certain R-substituents in specific positions using specific reagents under specific conditions provided regioselectively synthesized a series of aminated pyridine compounds with high yields. These substitution reactions may proceed via pyridyne intermediates.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Dimitrije Djukanovic, Maximilian A. Ganiek, Kohei Nishi, Konstantin Karaghiosoff, Kazushi Mashima, Paul Knochel
Summary: A new convenient method for the preparation of dicarbamoylzincs is reported in this study. The target compounds were obtained by reacting ZnCl2 and formamides or TMP2Zn with formamides. This method is compatible with sensitive functional groups such as esters, ketones, or nitro groups. The reaction of these dicarbamoylzincs with various functionalized allylic, benzylic, aryl, alkenyl compounds, acid chlorides, aldehydes, or enones resulted in the synthesis of polyfunctional amides in high yields. The C-13 NMR characterization of these new compounds is presented.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Andreas Hess, Nurtalya Alandini, Yusuf C. Guersoy, Paul Knochel
Summary: A new and storable magnesium amide was prepared and found to be suitable for the non-cryogenic magnesiation of fluoro-substituted arenes and heteroarenes. Further reactions produced a range of polyfunctional fluoro-substituted unsaturated building blocks.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Johannes H. Harenberg, Rajasekar Reddy Annapureddy, Konstantin Karaghiosoff, Paul Knochel
Summary: This study reports a lateral sodiation reaction for alkyl(hetero)arenes using a hexane-soluble sodium compound generated on demand, in the presence of TMEDA. The reaction can be conducted under batch and continuous flow conditions. The resulting benzylic sodium species can react with various electrophiles. This method has great potential for synthetic applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Saroj Kumar Rout, Agonist Kastrati, Harish Jangra, Kuno Schwaerzer, Alisa S. Sunagatullina, Maximilien Garny, Fabio Lima, Cara E. Brocklehurst, Konstantin Karaghiosoff, Hendrik Zipse, Paul Knochel
Summary: DFT calculations can predict the reactivity of uncommon N-heterocyclic scaffolds and facilitate their functionalization. Experimental results show that specific catalysts and reagents can achieve the regioselective derivatization of these compounds.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Alexander Kremsmair, Alisa S. Sunagatullina, Leonie J. Bole, Pasquale Mastropierro, Simon Grassl, Henrik R. Wilke, Edouard Godineau, Eva Hevia, Paul Knochel
Summary: A new method for selectively zincating challenging N-heterocyclic substrates has been reported using mixed Li/Zn bases. The method allows for mild regioselective reactions and provides insights into the composition and reactivity of the reaction mixtures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Alisa S. Sunagatullina, Ferdinand H. Lutter, Konstantin Karaghiosoff, Paul Knochel
Summary: We have developed a new iron-catalyzed reaction for converting alkyl iodides into alkylzinc iodides. The reaction exhibits diastereoselective ring closures when a remote double bond is present at position 5. Furthermore, the resulting zinc reagents can be further reacted with various electrophiles under copper or palladium catalysis to provide diverse polyfunctional products.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Alexander Kremsmair, Henrik R. R. Wilke, Johannes H. H. Harenberg, Benjamin R. G. Bissinger, Matthias M. M. Simon, Nurtalya Alandini, Paul Knochel
Summary: This study reports a practical in situ quench procedure for the generation of chiral secondary alkyl lithiums from secondary alkyl iodides. The reaction can be carried out in the presence of various electrophiles, resulting in the preparation of a wide range of optically enriched organic compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Alisa S. Sunagatullina, Andreas Hess, Alexander Kremsmair, Yifan Li, Yi-Hung Chen, Paul Knochel
Summary: We present a novel electrophilic amination method for primary, secondary, and tertiary alkyl, benzylic, and allylic zinc and magnesium organometallics using O-2,4,6-trimethylbenzoyl hydroxylamines (O-TBHAs) with yields ranging from 52-99%. These O-TBHAs exhibit excellent long-term stability and can be conveniently synthesized from various highly functionalized secondary amines through a three-step procedure. The amination reactions demonstrate remarkable chemoselectivity without the need for transition-metal catalysts, and are typically completed within 1-3 hours at 25 degrees Celsius. Furthermore, this electrophilic amination process enables the synthesis of enantioenriched tertiary amines (up to 88% ee) using optically enriched secondary alkylmagnesium reagents of the type s-AlkylMgCH(2)SiMe(3).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Clemence Hamze, Julie Brossier, Konstantin Karaghiosoff, Edouard Godineau, Paul Knochel
Summary: A regioselective tri- and tetra-functionalization of the pyridazine scaffold was achieved using two readily available building blocks, resulting in the synthesis of a range of pyridazine derivatives.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Agonist Kastrati, Alexander Kremsmair, Alisa S. Sunagatullina, Vasilii Korotenko, Yusuf C. Guersoy, Saroj K. Rout, Fabio Lima, Cara E. Brocklehurst, Konstantin Karaghiosoff, Hendrik Zipse, Paul Knochel
Summary: Straightforward calculations have led to the development of a set of organometallic reactions for the regioselective functionalization of the underexplored fused N-heterocycle imidazo[1,2-a]pyrazine. These reactions provide a way to access polyfunctionalized imidazopyrazine heterocycles.
Article
Chemistry, Multidisciplinary
Andreas Hess, Nurtalya Alandini, Hasret C. Guelen, Jan P. Prohaska, Paul Knochel
Summary: We report the preparation of a new hydrocarbon-soluble magnesium amide TMP2Mg (TMP = 2,2,6,6-tetramethylpiperidyl). This base showed excellent properties for the regioselective magnesiation of various arenes and heteroarenes bearing ethyl esters and carbamates under very mild reaction conditions. Subsequent trapping with aryl iodides (Negishi cross-coupling) gave access to a range of highly functionalized valuable building blocks.
CHEMICAL COMMUNICATIONS
(2022)
