Article
Chemistry, Multidisciplinary
Kananat Naksomboon, Enrique Gomez-Bengoa, Jaya Mehara, Jana Roithova, Edwin Otten, M. Angeles Fernandez-Ibanez
Summary: Pd-catalyzed C-H functionalization reactions of non-directed substrates have emerged as a promising alternative to the use of directing groups. A new type of S,O-ligand has been found to be highly efficient in promoting Pd-catalyzed C-H olefination reactions of non-directed arenes, although its role in the process was unclear. Through various mechanistic tools, it was discovered that C-H activation is the rate-determining step and the S,O-ligand triggers the formation of more reactive Pd cationic species, explaining the observed acceleration of the reaction. These findings provide important insights into the role of the S,O-ligand in promoting Pd-catalyzed C-H functionalization reactions.
Article
Chemistry, Multidisciplinary
Michael G. J. Doyle, Alexis L. Gabbey, Wesley McNutt, Rylan J. Lundgren
Summary: In this study, electron-deficient arylacetates were utilized as benzyl nucleophile surrogates to successfully generate enantioenriched acyclic molecules containing quaternary carbon centers via a two-step substitution-decarboxylation process. Products were often obtained with >90% ee using a commercially available catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Kangmei Wen, Mengxia Feng, Qiwen Gao, Chen Chen, Yinrong Wu, Jiamin Zhou, Liangbin Huang, Xiaodong Tang
Summary: In this study, synergistic copper/amine-catalyzed reactions were used to directly a-benzylate carbonyl compounds with arylacetic acids. These reactions demonstrate the first examples of decarboxylative oxidative synergistic transition-metal/enamine catalysis for a-functionalizing carbonyl compounds. The process is characterized by availability of starting materials, good tolerance towards functional groups, mild reaction conditions, and high yields. Dibenzylated products were obtained in moderate yields under slightly modified reaction conditions, and some products underwent acid-catalyzed intermolecular cyclization reactions with indoles to form 1,2,3,4-tetrahydrocyclopenta[b]indole derivatives. Furthermore, biological studies revealed that some of the products possess anticancer properties and may be beneficial for drug discovery studies.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Dennis Popp, Sven M. Elbert, Chantal Barwig, Julian Petry, Frank Rominger, Michael Mastalerz
Summary: The palladium-catalyzed cyclotrimerization of ortho-silylaryl triflates is a well-established method for synthesizing polycyclic aromatic hydrocarbons with triphenylene cores. In the reaction of pyrene with o-silylaryl triflates, higher homologues with eight- and ten-membered rings were unexpectedly formed along with the trimer, and a protocol was developed to isolate all members of this series. This novel class of PAHs was thoroughly investigated using various techniques, including X-ray diffraction, UV/Vis and fluorescence spectroscopy, and theoretical calculations. A mechanistic proposal for the formation of all higher cyclooligomers was supported by density functional theory (DFT) calculations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Qiang Dai, Lu Liu, Junliang Zhang
Summary: This study successfully achieved the kinetic resolution of rac-secondary phosphine oxides via enantioselective P-benzylation catalysis, delivering both tert- and sec-phosphine oxides in good yield and excellent enantiopurity. The synthetic utilities were further demonstrated by the facile preparation of valuable P-chiral compounds, precursors of bidentate ligands, and transition metal complexes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Xingwei Cai, Yang Shen, Wei Li, Wentao Zhan, Fanjun Zhang, Chen Xu, Heng Song
Summary: In this study, an efficient tungsten-catalyzed homogeneous system was developed for the selective synthesis of various azoaromatics, azoxyaromatics, and 2-substituted indolone N-oxides from anilines. This was achieved by regulating the reaction solvent with peroxide as a terminal oxidant under additive-free conditions. These findings not only provide an experimental framework for exploring tungsten catalysis in organic synthesis but also offer an efficient and convenient tactic for the selective oxidation of anilines.
Article
Chemistry, Organic
Kou Onodera, Ryo Takashima, Yumiko Suzuki
Summary: This study utilized acylals as building blocks for selective cross-benzoin synthesis via N-heterocyclic carbene-catalyzed reactions, successfully synthesizing O-acyl cross-benzoins. The combination of ortho-substituted phenyl acylals and aromatic/aliphatic aldehydes as coupling substrates using bicyclic triazolium salts as precatalysts and potassium carbonate as a base in THF at reflux temperature selectively yielded the desired products.
Article
Chemistry, Multidisciplinary
Mohan Chandra Sau, Smita Mandal, Manish Bhattacharjee
Summary: Monoallylation and monoalkylation of diketones and beta-keto esters with allylic and benzylic alcohols catalyzed by [Cp*Co(CH3CN)(3)][SbF6](2) have been reported, yielding regioselective products for the synthesis of trisubstituted pyrazoles and one pyrazolone. Mechanistic investigations revealed reactions proceed via eta(3)-allyl complex formation or ally ether intermediate for allylation, while alkylation takes place solely via ether intermediate.
Article
Chemistry, Multidisciplinary
Pengpeng Zhang, Jin Wang, Zoe R. Robertson, Timothy R. Newhouse
Summary: This report presents a general, mild, and effective nickel-catalyzed benzylic allylation and benzylation of various heterocyclic aromatic compounds, with exquisite selectivity for the benzylic sites at the 2-position. The method shows promise for the synthesis of complex molecules and library diversification in drug discovery.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Chao Liu, Jiahao Wu, Xiangwen Tan, Jinhui Zhang, Wanqing Wu, Huanfeng Jiang
Summary: In this study, the intermolecular oxyamination reaction of aromatic amines and unactivated alkenyl carbonyl compounds under palladium catalysis was successfully achieved. Both primary and secondary aromatic amines efficiently yielded the corresponding β-arylamino-γ-lactones. The key step in this process involved a Pd-II/Pd-IV catalytic cycle incorporating a 1,2-(C-N)/(C-O) dyotropic rearrangement. The reaction exhibited mild reaction conditions and good functional group compatibility.
Article
Chemistry, Organic
Chaoyin He, Xiaodong Fan, Mengmeng Ji, Xinhui Sun, Weiya Zhang, Xianghui Zhu, Zhizhong Sun, Wenyi Chu
Summary: A visible-light-induced strategy for the synthesis of phenolic compounds was developed using nitrogen-heterocyclic directing groups and hydrogen peroxide as a hydroxylation reagent. The method provides a new solution for the preparation of phenolic compounds by C-H bond activation hydroxylation, with good functional group tolerance, wide substrate scope, and successful application in the synthesis of natural products and drugs.
TETRAHEDRON LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Saori Tsuzuki, Shunya Sakurai, Akira Matsumoto, Taichi Kano, Keiji Maruoka
Summary: This study describes a Ni-catalyzed direct C-H alkylation of N-quinolylbenzamides using alkylsilyl peroxides as alkyl-radical precursors. The reaction forms a new C(sp(3))-C(sp(2)) bond via selective cleavage of both C(sp(3))-C(sp(3)) and C(sp(2))-H bonds. Due to the structural diversity of alkylsilyl peroxides, a wide range of alkyl chains including functional groups and complex structures can be introduced at the ortho-position of readily available N-quinolylbenzamide derivatives.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Halina Kaczmarek, Agnieszka Tafelska-Kaczmarek, Katarzyna Roszek, Joanna Czarnecka, Beata Jedrzejewska, Katarzyna Zblewska
Summary: In this study, fluorescent chitosan derivatives were synthesized and their potential applications in medicine and various industrial sectors were evaluated. The derivatives showed strong resistance to UV-C radiation, indicating their suitability for use in these fields.
Article
Environmental Sciences
Joy McGrath, Gordon Getzinger, Aaron D. Redman, Melanie Edwards, Alberto Martin Aparicio, Eleni Vaiopoulou
Summary: This study examined the applicability of the TLM model to heterocyclic aromatic compounds and found that adjusting the coefficient could successfully describe the toxicity of these compounds. Heterocyclic compounds exhibit higher affinity and toxicity, possibly due to the role of hydrogen bonding accepting moieties.
ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yunlong Zhao, Chen-Fei Liu, Leroy Qi Hao Lin, Albert S. C. Chan, Ming Joo Koh
Summary: In this study, a N-heterocyclic carbene-Ni-I catalytic species was used to achieve highly substituted alkenes from abundant monosubstituted substrates with excellent regio- and stereoselectivities. Trimethylsilyl triflate and trimethylamine additives were added to mediate the reaction, resulting in the generation of trisubstituted boron- and arene-containing trans alkenes. This method represents a significant addition to the toolbox of reactions for the concise synthesis of unsaturated biologically active compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
