Article
Chemistry, Multidisciplinary
Yong Wu, Shanshan Cao, Iskander Douair, Laurent Maron, Xihe Bi
Summary: The [2+1] cycloaddition reaction of a metal carbene with an alkene often suffers from side reactions, leading to lower yields of cyclopropanation products. By adding a low concentration of diazo compound to alkenes, it was found that AgOTf catalysis can efficiently produce cyclopropane products from hindered alkenes.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Leonardo de S. da Silva, Alexandre A. de Souza, Egil Sa
Summary: Iron-carbenes with heme or piano-stool groups as ancillary ligands are important catalysts for cyclopropanation through carbene transfer to olefins. The reaction mechanism operates through a concerted or stepwise pathway. The diastereo selectivity is mainly related to non-covalent interactions in transition structures of the main barriers in the mechanisms.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Qing-Zhu Li, Yan-Qing Liu, Xin-Xin Kou, Wen-Lin Zou, Ting Qi, Peng Xiang, Jin-Dun Xing, Xiang Zhang, Jun-Long Li
Summary: In this study, an unprecedented oxidative radical NHC catalysis using peroxyester as the external oxidant was reported, enabling divergent difunctionalization of olefins. This methodology allows for efficient synthesis of value-added compounds in a cost-effective manner using commonly used chemicals.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Johannes Nebauer, Christian Neiss, Marcel Krug, Alexander Vogel, Dominik Fehn, Shuhei Ozaki, Frank Rominger, Karsten Meyer, Kenji Kamada, Dirk M. Guldi, Andreas Goerling, Milan Kivala
Summary: This article describes a new type of nitrogen-centered polycyclic scaffold synthesized through intramolecular oxidative cyclodehydrogenation of tri(1-naphthyl)amine, which is the first example of a direct 3-fold cyclization of a triarylamine under oxidative conditions. Experimental and theoretical studies reveal the impact of cyclization on the electronic and photophysical properties, and mechanistic studies suggest the cyclization occurs under kinetic control via a dicationic mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Jingyang Qin, Manuel Barday, Samikshan Jana, Nil Sanosa, Ignacio Funes-Ardoiz, Christopher J. Teskey
Summary: A mild and selective hydropyridylation method for dienes was reported, allowing for traceless coupling of dienes on a wide range of pyridine substrates. The method showed good functional group tolerance, making it suitable for late-stage functionalization. The mechanistic pathway involved non-reversible hydrogen atom transfer, resulting in a reaction that was uniquely selective for dienes in the presence of other olefins.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jona Merx, Kas J. Houthuijs, Hidde Elferink, Eva Witlox, Jasmin Mecinovic, Jos Oomens, Jonathan Martens, Thomas J. Boltje, Floris P. J. T. Rutjes
Summary: This study characterized cyclic N-acyliminium ions in the gas phase through collision induced dissociation tandem mass spectrometry and infrared ion spectroscopy, providing valuable insights into their conformations through comparison of DFT calculated spectra with experimentally observed IR spectra.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Thomas Hansen, Tim P. Ofman, Joey G. C. Vlaming, Ivan A. Gagarinov, Jessey van Beek, Tessa A. Gote, Jacoba M. Tichem, Gijs Ruijgrok, Herman S. Overkleeft, Dmitri V. Filippov, Gijsbert A. van der Marel, Jeroen D. C. Codee
Summary: By systematically studying the reactivity-stereoselectivity relationships of caryophyllose donor and acceptor glycosides, using experimental and computational techniques, we were able to design carbohydrate building blocks with the necessary properties to assemble mycobacterial lipooligosaccharide fragments of M. marinum.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Benedikt Wolff, Zheng-Wang Qu, Stefan Grimme, Martin Oestreich
Summary: This study presents a method for the enantioselective reduction of simple carbenium ions using cyclohexadienes with a hydridic C-H bond at an asymmetrically substituted carbon atom. Chiral cyclohexadienes are used as dihydrogen surrogates for the transfer hydrogenation of alkenes (styrenes). The reaction mechanism involves the initiation by trityl cation and a delicate intermolecular capture of a carbenium-ion intermediate by the chiral hydride source, resulting in good enantiomeric ratios of the reduction products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Bo-Han Zhu, Ying-Qi Zhang, Hao-Jin Xu, Long Li, Guo-Cheng Deng, Peng-Cheng Qian, Chao Deng, Long-Wu Ye
Summary: An efficient copper-catalyzed tandem alkyne hydration/intramolecular Mannich reaction has been investigated for the synthesis of valuable compounds. This method allows the efficient synthesis of 3,4-dihydro-2-quinolones with high regio-, diastereo-, and enantioselectivity.
Article
Chemistry, Inorganic & Nuclear
Leonard Karl, Jan Meisner, Christian Ganter
Summary: Attempts were made to synthesize two novel four-membered 1,3-diazetidine based N-heterocyclic carbenes (NHCs) with an organic backbone and a carbonyl functionality. Although the isolated carbenes were not achieved, their respective carbene dimers were obtained in quantitative yield and underwent degradation and rearrangement upon thermal exposure. Some of the thermal reaction species were isolated and characterized, while others were observed using mass spectrometry. Ab initio and density functional theory (DFT) calculations provided a mechanistic explanation for the experimental observations. Classic carbene trapping reactions are still a goal to be achieved due to the strong preference for dimerization.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Hiroki Tashiro, Masahiro Terada, Itaru Nakamura
Summary: Gold-catalyzed reactions were used to synthesize 2H-azirines with sulfenyl and acyl groups at the 3-position, yielding good to excellent results. These reactions involved internal transfer of sulfinyl oxygen atom and carbene insertion into the N-S bond for ring construction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Sebastian Mummel, Felix Lederle, Eike G. Huebner, Jan C. Namyslo, Martin Nieger, Andreas Schmidt
Summary: Sydnone methides are rare compounds that can form pi-electron rich anionic N-heterocyclic carbenes and coordinate with various metals, while also undergoing C-C coupling reactions under specific catalysts. Studies have determined their electronic properties and NMR spectra.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Amalia-Sofia Piticari, Daniele Antermite, Joe Higham, J. Harry Moore, Matthew P. Webster, James A. Bull
Summary: This study achieved the selective Pd-catalyzed C-H cis-functionalization of piperidine and tetrahydropyran carboxylic acids using a C(4) aminoquinoline amide auxiliary. High mono- and cis-selectivity was obtained by adding mesityl carboxylic acid. The reaction conditions developed in this study had significantly lower temperatures compared to other reported heterocycle C(sp(3))-H functionalization reactions, and a one-pot C-H functionalization-epimerization procedure was established to directly obtain the trans-3,4-disubstituted isomers. Diverse aminoquinoline removals were achieved by installing carboxylic acid, alcohol, amide, and nitrile functional groups. Overall, fragment compounds suitable for screening were synthesized in 3-4 steps from readily-available heterocyclic carboxylic acids.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Min Zhang, Yang Wang, Shi-Jun Li, Xinghua Wang, Qianqian Shi, Xue Li, Ling-Bo Qu, Donghui Wei, Yu Lan
Summary: This study proposes an NHC and NHC center dot H+ cooperative catalytic model for inert C-C bond activations, and uses density functional theory calculations to discover two ways in which the organocatalyst functions in [4 + 2] annulation reactions. It also introduces an atomic electronegativity index to predict the site of stereoselective C-C bond formation accurately.
Article
Chemistry, Multidisciplinary
Ramon Arora, Jose F. Rodriguez, Andrew Whyte, Mark Lautens
Summary: A palladium-catalyzed strategy has been proposed for synthesizing unsymmetrically linked heterocycles within stereoselective tetrasubstituted olefins, with high yields and excellent stereoselectivities achieved using low catalyst loadings. Mechanistic studies suggest a syn-carbopalladation of the carbamoyl chloride followed by Pd-II-catalyzed cyclization of alkyne-tethered nucleophiles.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
