Article
Chemistry, Multidisciplinary
Jingyan Luo, Zhou Luo, Biqi Zhang, Qiuyu Zhao, Lu Liu, Yuanyuan Liu
Summary: We report a highly chemoselective consecutive C-H [2+3]-cyclative functionalization for the simultaneous formation of two C-C bonds, constructing polycyclic phenols without the use of metal catalyst. The catalytic system, using commercially available and low-cost B(C6F5)(3), tolerates a wide range of substrates and efficiently produces 2,6,7,8-tetrahydroacenaphthylen-3-ol-type polycyclic compounds. Additionally, several derivative reactions of the catalytic products demonstrate the potential application of this method in the synthesis of polycyclic compounds.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Huaquan Fang, Kaixue Xie, Sebastian Kemper, Martin Oestreich
Summary: The study demonstrates that Tris(pentafluorophenyl)borane catalyzes the two-fold C(sp(3))-H silylation of various trialkylamine derivatives with dihydrosilanes, resulting in the formation of 4-silapiperidines in decent yields. The reaction cascade involves amine-to-enamine dehydrogenation at two alkyl residues and two electrophilic silylation reactions of those enamines, one inter- and one intramolecular.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Manman Sun, Rong Zhong, Jinshan Li, Yongmin Ma, Jianguo Yang, Zhiming Wang
Summary: A metal-free 1,4-allylation of azadienes with allyltrimethylsilanes catalyzed by B(C6F5)(3) has been developed. The high Lewis acidity, good thermal stability, and good hydrolytic stability of the catalyst make this reaction efficient and operationally simple. Benzofuran-, indene-, dihydronaphthalene-, chromene-, and benzothiophene-based allyl arylmethanes have been obtained in up to 95% yield.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yuntong Li, Wen-Qiang Wu, Hui Zhu, Qi-Kai Kang, Lun Xu, Hang Shi
Summary: In this study, we report Rh-catalyzed benzylic addition of alkylarenes to Michael acceptors, which involves the activation of the aromatic ring for deprotonation of the unactivated benzylic C-H bond and addition of the resulting carbanion to the α,β-unsaturated double bond. This byproduct-free method provides access to all-carbon quaternary centers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Chang-Peng Zou, Tao Ma, Xiu-Xiu Qiao, Xi-Xi Wu, Ganpeng Li, Yonghui He, Xiao-Jing Zhao
Summary: The beta-C-H functionalization of tertiary amines was achieved via the B(C6F5)(3)-catalyzed borrowing hydrogen strategy, leading to the synthesis of 1,3-diamines containing the indolin-3-one moiety in high yields. A possible catalytic cycle was proposed to explain the reaction process. Notably, the beta-C-H alkylation of amines is external oxidant- and transition-metal-free, making it economically favorable for chemical synthesis.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Jianbo Tang, Jian-Fei Bai, Jinfeng Zheng, Shuangshuang Li, Zhi-Jiang Jiang, Jia Chen, Kun Gao, Zhanghua Gao
Summary: A method for the deuteration of intra- and extra-cyclic methylene in cyclic ethers using D2O as a deuterium source has been developed, resulting in moderate yield and excellent deuterium incorporation. The transformation shows remarkable tolerance towards functional groups in a wide range of alkynols, and the key factor for achieving high deuterium incorporation is the hydrogen isotope exchange reaction of an unstable oxonium ion. This novel methodology provides an efficient and concise synthetic route to valuable deuterated cyclic ethers that are often challenging to prepare using other methods.
Article
Chemistry, Applied
Jiaming Zhou, Jin Huang, Changhui Lu, Huanfeng Jiang, Liangbin Huang
Summary: A B(C6F5)(3)-catalyzed hydroarylation of terminal alkynes with various phenols at room temperature was developed, leading to the synthesis of 2-gem-vinylphenols with good regio-selectivity. The transformations exhibited a broad substrate scope with moderate yields, and mechanism studies suggested the activation of phenol by B(C6F5)(3) followed by protonation of the alkyne/Friedel-Crafts-type reaction.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Physical
Garrett P. R. Freure, Eric A. Skrotzki, Jean-Danick E. Lavertu, Stephen G. Newman
Summary: Various methods have been investigated recently for the arylation of weakly acidic C(sp(3))-H bonds, with this study focusing on a base-mediated approach using organometallic superbases. The study developed conditions for high selectivity metalation using either n-BuLi/diamine or n-BuLi/KOtBu superbases, allowing for direct use in cross-coupling or formation of organozincs for reactions with functional groupdense organohalides.
Article
Chemistry, Multidisciplinary
Yunbo Zhao, Dipendu Mandal, Jing Guo, Yile Wu, Douglas W. Stephan
Summary: The study demonstrates a metal-free catalytic selective N-1 alkylation of benzotriazoles with diazoalkanes using 10 mol% of B(C6F5)(3), providing N-1-alkylated benzotriazoles in good to excellent yields. The protocol is successfully applied to gram-scale syntheses and a derivative with antimicrobial activity, showcasing its versatility and potential for practical applications.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Xiaoqin Ning, Yongke Chen, Fangdong Hu, Ying Xia
Summary: This study presents the palladium-catalyzed cross-coupling reactions of cyclobutanone-derived N-sulfonylhydrazones with aryl or benzyl halides, demonstrating that the metal carbene process and beta-hydride elimination can occur smoothly in strained ring systems to yield structurally diverse products. The preliminary success in asymmetric carbene coupling reactions in strained ring systems offers a promising route for the synthesis of enantioenriched four-membered-ring molecules.
Article
Chemistry, Physical
Teng Cao, Caicai Gao, Alexander M. Kirillov, Ran Fang, Lizi Yang
Summary: The mechanism and stereoselectivity in the B(C6F5)3-catalyzed cyclopropanation of styrenes and aryldiazoacetates were studied using density functional theory (DFT), revealing key observations. The results are significant for the design and prediction of homogeneous catalytic molecular systems and [2 + 1] cycloaddition transformations.
MOLECULAR CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Zhikun Liang, Lei Wang, Yu Wang, Lifan Wang, Qinglei Chong, Fanke Meng
Summary: This study presents a series of cobalt-catalyzed carbon-carbon bond forming reactions of cyclobutenes initiated through enantioselective carbometalation. Mechanistic studies reveal an unusual 1,3-cobalt migration and subsequent beta-carbon elimination cascade process in the allyl addition. These findings establish a new elementary process for cobalt catalysis and expand the diversity of nucleophiles for enantioselective transformations of cyclobutenes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Tianhong Yan, Yahui Li, Guanglong Huang, Shaofei Ni, Li Dang
Summary: Mechanistic study on B(C6F5)(3)-catalyzed hydrostannation and dehydrogenative stannylation of phenylacetylene was conducted.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Arnab Dey, Anurag Singh, Chandra M. R. Volla
Summary: The efficient oxidative [3 + 2] annulation reaction of aryl hydrazones and heterobicyclic alkenes has been achieved using inexpensive cobalt salts under aerobic conditions. The reaction generates complex indane derivatives with high anti-diastereoselectivity, avoiding the use of stoichiometric amounts of metal oxidants.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Qiaotian Wang, Wei Meng, Xiangqing Feng, Haifeng Du
Summary: A novel mode for the activation of N-heterocyclic carbene boranes was developed in this work by generating highly reactive zwitterion species. The B(C6F5)3-catalyzed hydroboration of a wide range of alkenes led to good to high yields of desired products with excellent regioselectivities in some cases. The study also proposed mechanisms involving B-H bond cleavage and electrophilic addition for further exploration in the future.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yuya Hu, Zhihong Wei, Anna Frey, Christoph Kubis, Chang-Yue Ren, Anke Spannenberg, Haijun Jiao, Thomas Werner
Summary: Hydroxy-functionalized phosphonium salts were studied as bifunctional catalysts for the conversion of CO2 with epoxides, with the phenol-based phosphonium iodide catalyst showing excellent efficiency. Under optimized conditions, the catalyst successfully converted epoxides to cyclic carbonates with high yields, demonstrating potential for pharmaceutical synthesis. DFT calculations rationalized the mechanism and efficiency of the phenol-based catalyst, highlighting the importance of hydrogen bonding in facilitating the ring-opening step.
Article
Chemistry, Applied
Xin Liu, Thomas Werner
Summary: The manganese catalyzed coupling of alcohols with phosphorus ylides was found to be controllable in terms of selectivity for forming carbon-carbon single and double bonds by adjusting ligands and reaction conditions. Compared to previous methods using precious metal complexes, this system utilizes earth abundant manganese catalysts, allowing for C-C and C=C bond formation in a sequential one-pot reaction. Mechanistic studies revealed that C-C bonds were generated through a borrowing hydrogen pathway, while C=C bond formation followed an acceptorless dehydrogenative coupling pathway.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Vivian Stefanow, Aiga Grandane, Marcus Eh, Johannes Panten, Anke Spannenberg, Thomas Werner
Summary: The natural compound (-)-alpha-cedrene has a weak woody and cedarlike odor, while the derivative cis-cedrene acetonide is a very powerful semisynthetic aroma molecule. The synthesis of cis-cedrene acetonide starting from cedrene can achieve an overall yield of <20%. Two synthetic pathways have been reported in this work, with the highest overall yield reaching 78%. An attempt to prepare the cis-diol with inverted stereochemistry was also made, resulting in the undesired trans-product in >99% yield.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2021)
Article
Chemistry, Organic
Linda Pudnika, Ilona Domraceva, Thomas Werner, Raivis Zalubovskis, Aiga Grandane
Summary: The study successfully synthesized compounds with potential biological activity containing benzoxepinone core structures through a simple and efficient synthetic route, and obtained diverse derivatives through late stage modification. This method is highly applicable for high throughput applications and provides a convenient pathway for further functionalization.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Physical
David K. Leonard, Wu Li, Nils Rockstroh, Kathrin Junge, Matthias Beller
Summary: The stability of C(sp3)-C(sp3) bonds poses a challenge for the site-selective activation in synthetic chemistry. A new method using a cheap iron catalyst and air as oxidant successfully cleaves these bonds in specific amine derivatives, with the rapid development of the catalytic process facilitated by a statistical design of experiments (DoE).
CATALYSIS COMMUNICATIONS
(2021)
Review
Chemistry, Multidisciplinary
Sara Kopf, Florian Bourriquen, Wu Li, Helfried Neumann, Kathrin Junge, Matthias Beller
Summary: Organic compounds labeled with hydrogen isotopes are crucial in drug discovery and development in the pharmaceutical industry. Recent advancements have been made in methodologies for isotopic enrichment of organic molecules, including hydrogen isotope exchange reactions, isotopically labeled analogues of organic reagents, and other transformations with isotope incorporation.
Article
Chemistry, Multidisciplinary
Wu Li, Jabor Rabeah, Florian Bourriquen, Dali Yang, Carsten Kreyenschulte, Nils Rockstroh, Henrik Lund, Stephan Bartling, Annette-Enrica Surkus, Kathrin Junge, Angelika Brueckner, Aiwen Lei, Matthias Beller
Summary: Isotope labelling, especially deuteration, is an important tool for drug development, allowing for identification and quantification of metabolites. This study demonstrates a scalable and efficient method for selective deuteration using a nanostructured iron catalyst.
Article
Chemistry, Organic
Changyue Ren, Anke Spannenberg, Thomas Werner
Summary: The synthesis of three bifunctional phosphonium salts with perfluorinated side chains is reported as catalysts for the synthesis of cyclic carbonates from epoxides and CO2. The most efficient catalyst with a phenolic substructure allows the synthesis of various carbonates at room temperature and low CO2 pressure. The use of perfluorodecalin improves yields and facilitates catalyst separation. However, the activity of recycled catalysts gradually decreases.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Constanza Terazzi, Karoline Laatz, Jan von Langermann, Thomas Werner
Summary: A simple catalytic system consisting of CaI2 and Et3N was used to efficiently cycloaddition of CO2 to a variety of epoxides, producing high yields of carbonates. The reaction mechanism involves the coordination of the amine to the Lewis acidic calcium center and the activation of the epoxide.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Physical
Constanza Terazzi, Anke Spannenberg, Jan von Langermann, Thomas Werner
Summary: The biocatalytic kinetic resolution of cyclic carbonates derived from glycerol was achieved using esterases and lipases. Pig Liver Esterase and Novozym (R) 435 showed the best selectivity, with E values of 38 and 49, respectively. The resolution of halogenated carbonates resulted in highly selective unconverted enantiomer, and Novozym (R) 435 showed good recyclability and stability.
Article
Plant Sciences
Pierre Yemback, Kenneth O. Eyong, Noella M. Efange, Michael HK. Kamdem, Derek T. Ndinteh, Patricia O. Odumosu, Gabriel N. Folefoc, Lawrence Ayong, Thomas Werner
Summary: Compounds from the Cameroon Natural Product Library (CANAPL) were screened against the enzyme target PfGAPDH to discover potential antimalarial agents. Lupeol cinnamate and oleanane cinnamate were identified as hits, and structurally similar triterpenoids from Baillonella toxisperma were isolated and screened. The optimized lupane derivatives showed potent antiplasmodial activities, with betulonic acid acryl aldehyde exhibiting the highest activity (IC50 = 0.703μM).
PHYTOCHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Changyue Ren, Constanza Terazzi, Thomas Werner
Summary: This paper reports an environmentally friendly organocatalytic N-formylation and N-methylation reaction of amines using CO2 as the C1 source and hydrosilanes as the reductant. By choosing different reductants and catalysts, selective conversion of substrates can be achieved, leading to the synthesis of a range of compounds.
Article
Chemistry, Physical
Constanza Terazzi, Anke Spannenberg, Jan von Langermann, Thomas Werner
Summary: The biocatalytic kinetic resolution of cyclic carbonates derived from glycerol was investigated in this study. A selection of enzymes was tested, and Pig Liver Esterase and Novozym (R) 435 showed the highest selectivity. The enzymes were successfully used for the conversion of 12 glycerol derivatives, and the resolution of halogenated carbonates exhibited excellent enantiomeric excess. Furthermore, Novozym (R) 435 showed good recyclability, retaining its activity after 10 cycles of reuse. The chiral carbonate obtained was further used for the synthesis of pharmaceutical compounds with high yield and enantiomeric ratio.
Article
Chemistry, Multidisciplinary
Wu Li, Ruiyang Qu, Weiping Liu, Florian Bourriquen, Stephan Bartling, Nils Rockstroh, Kathrin Junge, Matthias Beller
Summary: The introduction of deuterium atoms into organic compounds is essential for basic chemistry, material sciences, and drug development in the pharmaceutical industry. Researchers have developed a practical and stable heterogeneous copper catalyst for dehalogenative deuteration via water-gas shift reaction at low temperature. This method shows potential for organic synthesis and medicinal chemistry.
Article
Chemistry, Multidisciplinary
Xin Liu, Thomas Werner
Summary: A manganese pincer complex is reported as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes, leading to the corresponding alcohols, amines, and methanol. This method represents an approach to the indirect reduction of CO2 and shows the first examples of reduction of carbamates and urea derivatives as well as C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is demonstrated by successful reduction of various compounds with good to excellent yields.
