Article
Chemistry, Multidisciplinary
Shivam A. A. Meena, Poonam Sharma, Akhilesh K. K. Verma
Summary: A transition-metal-free one-pot synthesis of di-functionalized succinimides has been developed, which involves a radical cascade seleno/thiosulfonation of aza-1,6-enynes in an atom economical manner. This method allows the synthesis of highly decorated succinimides with excellent stereoselectivity under mild reaction conditions. The proposed radical pathway is well supported by control experiments. The reaction demonstrates advantageous features including operational simplicity, atom economy, and broad substrate scope.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Yingming Ren, Yaxin Ge, Qinqin Yan, Yunfei Tian, Jilai Wu, Yujie Yang, Lijun Li, Zejiang Li
Summary: A novel nitrohalogenation/cyclization reaction was developed using tert-butyl nitrite to introduce nitro and halo groups into organic compounds. Control experiments were conducted to explain the mechanism, and further functional transformations proceeded effectively in this reaction system.
Article
Chemistry, Multidisciplinary
Shi-Ping Wu, Dong-Kai Wang, Qing-Qing Kang, Guo-Ping Ge, Hongxing Zheng, Meiling Zhu, Ting Li, Jun-Qi Zhang, Wen-Ting Wei
Summary: This novel synthetic protocol utilizes a sulfonyl radical to trigger selective iodosulfonylation and bicyclization of 1,6-dienes, demonstrating high selectivity and efficiency, mild reaction conditions, excellent functional group compatibility, and broad substrate scope. It provides a unique platform for precise radical cyclization.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Liam M. Joyce, Stephen A. Moggach, Christopher J. T. Hyland, Stephen G. Pyne, Scott G. Stewart
Summary: A nickel-catalyzed tetradehydro-Diels-Alder reaction of (E)-3-ene-1,8-diynes has been developed for the synthesis of isoindolines, dihydroisobenzofurans, and tetrahydroisoquinolines. Air-stable nickel catalysts, including novel nickel(0)-phosphite catalysts, were employed in this study. Additionally, the mechanism of trapping nickellacycle intermediates with pinacolborane to yield vinyl boronates was discussed to gain insights into the initial cycloisomerization process.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Jian-Qiang Chen, Xiangxiang Luo, Meiling Chen, Yi Chen, Jie Wu
Summary: A novel alkoxycarbonyl-radical-triggered cascade cyclization of 1,7-enynes, with alkyloxalyl chlorides as the ester units, for the synthesis of benzo[j]phenanthridines is reported. The reaction conditions are compatible with a broad range of alkoxycarbonyl radical sources and enable the installation of an ester group in the polycyclic compound. This radical cascade cyclization reaction exhibits excellent functional group tolerance, mild reaction conditions, and good to excellent yields.
Article
Chemistry, Organic
Kenta Tanaka, Mami Kishimoto, Yuta Tanaka, Yusuke Kamiyama, Yosuke Asada, Mayumi Sukekawa, Naoya Ohtsuka, Toshiyasu Suzuki, Norie Momiyama, Kiyoshi Honda, Yujiro Hoshino
Summary: New moderately oxidizing thioxanthylium photoredox catalysts have been developed that can efficiently promote radical-cation Diels-Alder reactions under green light irradiation. These catalysts have relatively moderate excited-state reduction potentials and can tolerate beta-halogenostyrenes, producing synthetically useful halocyclohexenes.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Yan Zhang, Zhenzhi Cai, Chunhang Zhao, Hanliang Zheng, Lutz Ackermann
Summary: Electrooxidative radical cascade cyclization of 1,6-enynes enables the synthesis of sulfonamides with medium-sized rings. The activation barrier difference between alkynyl and alkenyl moieties allows for chemo-selective addition and regioselective ring formation. This metal-free and chemical oxidant-free reaction provides efficient access to sulfonamides with bridged or fused ring systems.
Article
Chemistry, Physical
Roel F. J. Epping, David Vesseur, Minghui Zhou, Bas de Bruin
Summary: Discovered in the 1970s as organometallic curiosities, carbene radicals have become essential in modern homogeneous catalysis. These radicals exhibit nucleophilic reactivity different from electrophilic Fischer carbenes. The successful catalytic application of carbene radicals has led to the synthesis of diverse carbon and heterocyclic compounds. This Perspective provides an overview of the coordination chemistry, reactivity, and catalytic application of carbene radicals using transition metal complexes and catalysts since 2011.
Review
Chemistry, Applied
Wen-Ting Wei, Qiang Li, Ming-Zhong Zhang, Wei-Min He
Summary: N-radicals have been relatively unexplored compared to carbon-centered radicals, but recent advancements in radical chemistry have led to the development of various production methods for N-radicals. These N-radicals play crucial roles in the cyclization of 1,n-enynes, providing a new synthetic pathway for the preparation of complex cyclic systems and natural products containing elaborate ring frameworks.
CHINESE JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Organic
Wei Dong, Zhuo-Yue Fang, Tong-Yang Cao, Jie-Hui Cao, Zi-Qiang Zhao, Linlin Zhang, Wei Li, Lin Qi, Li-Jing Wang
Summary: A facile copper-catalyzed aminosulfonylation method has been developed for the direct synthesis of potentially bioactive 1,3-oxazines using O-homoallyl benzimidates and sodium sulfinates in the presence of tert-butyl peroxybenzoate (TBPB) and XPhos ligand. This method offers the advantages of a cheap catalyst, easily available and stable sulfone reagents, and simple operation.
Review
Chemistry, Organic
Zhenzhi Cai, Sven Trienes, Kairui Liu, Lutz Ackermann, Yan Zhang
Summary: During the past decade, photo- and electrochemical reactions via single-electron-transfer (SET) triggered radical pathways have been widely used to efficiently form chemical bonds. In particular, radical cyclization reactions of 1,n-enynes have been explored for the synthesis of bioactive compounds. This minireview summarizes recent progress in radical cascade cyclizations of 1,n-enynes (n = 5, 6, and 7) under photo/electrochemical conditions until September 2023, providing a categorized overview and understanding for readers.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Lin-Ping Hu, De-Run Zhang, Xiao-Hong Huang, Feng-Lin Liu, Xia Li, Ming-Yu Teng, Guo-Li Huang
Summary: The method involves the aryl sulfonyl radical-triggered cascade cyclization of phenyl-linked 1,6-enynes to synthesize biologically important indenes containing alkenyl C-X bonds and 10a,11-dihydro-10H-benzo[b]fluorines. Three new chemical bonds, including C-S, C-C, and C-X bonds, and three C-C bonds are formed in one step. The metal-free, mild reaction conditions, broad substrate scope, and good functional group tolerance make the method attractive and valuable.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Review
Chemistry, Organic
Tian-Shu Zhang, Shuai Liu, Wen-Juan Hao, Bo Jiang
Summary: ortho-Alkynyl aryl ketones have been widely used in organic synthesis in the past decade due to their high reactivity and structural diversity. Four common intramolecular annulative patterns based on Baldwin's rule, including oxo-cyclization and carbocyclization, have been employed with the help of various catalysts or photocatalysis. With recent developments, ortho-alkynyl aryl ketones have become important building blocks for the construction of various scaffolds. This review provides an overview of the chemistry, reactivities, mechanisms, and applications of ortho-alkynyl aryl ketones.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Georgi R. Genov, Hiroki Takezawa, Harumi Hayakawa, Makoto Fujita
Summary: The TDDA reaction is a useful method to assemble complex molecular structures from simple precursors in a single step, but it requires careful design of substrates and harsh reaction conditions. In this study, we demonstrate an efficient and site-selective TDDA transformation within a self-assembled Pd6L4 cage. The encapsulation of substrates within the large cavity of the cage allows for enhanced cyclization rates and high selectivity for unsymmetrical substrates.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Shi-Yin Tian, Jing-Jing Ai, Jia-Hui Han, Weidong Rao, Shu-Su Shen, Daopeng Sheng, Shun-Yi Wang
Summary: A photocatalytic synthesis method was developed to simultaneously construct two C-S/Se bonds and one C-C bond without the use of transition metals or other additives, using diphenyl disulfide or diphenyl diselenide as sulfur or selenium sources.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Biophysics
Nadine Bauer, Ivan Maisuls, Abel Pereira da Graca, Dirk Reinhardt, Raghu Erapaneedi, Nils Kirschnick, Michael Schafers, Carsten Grashoff, Katharina Landfester, Dietmar Vestweber, Cristian A. Strassert, Friedemann Kiefer
Summary: Hypoxia plays a crucial role in regulating cell metabolism, migration, and angiogenesis, and is involved in various pathological conditions. In this study, novel genetically-encoded reporters, dUnORS and dUnOFLS, were developed to accurately assess oxygen gradients in cells using ratiometric measurement and FRET-FLIM analysis. These reporters showed promising results in visualizing oxygen availability in vivo.
BIOSENSORS & BIOELECTRONICS
(2023)
Article
Chemistry, Organic
Ruairi O. McCourt, Armido Studer
Summary: A 1,2-difunctionalization reaction of cyclic enol ethers mediated by bis(arylsulfonyl) peroxides is reported. Bis(nosyl) peroxide selectively adds a sulfonyl group at the 3-position of enol ethers, generating an oxocarbenium ion that is trapped by a carboxylic acid nucleophile at the 2-position. The reaction proceeds with good yield and tolerates a variety of cyclic enol ethers as well as different carboxylic acids as the oxocarbenium ion trapping reagents.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Yongjing Wang, Kang Ma, Tiantong Zhang, Philipp Alexander Held, Armido Studer, Harald Fuchs, Zhixin Hu, Zhixiang Sun, You Han, Hong-Ying Gao
Summary: The effect of iodine on modulating the self-assembly structures of organic molecules on metal surfaces was systematically studied. By using low-temperature scanning tunneling microscopy and density functional theory, the transformation of molecular self-assembly structures induced by iodine dosing on the Ag(111) surface was explored. It was found that iodine can modulate the self-assembly structure of organic molecules with weak intermolecular interaction, while those with stronger intermolecular hydrogen bonding are not affected. These findings were confirmed by density functional theory calculations.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Till Drennhaus, Dirk Leifert, Jessika Lammert, Jan Philipp Drennhaus, Klaus Bergander, Constantin G. Daniliuc, Armido Studer
Summary: In this study, enantioenriched chiral indoles were synthesized through a mild and efficient radical cascade reaction using a chiral copper-bisoxazoline complex. The targeted 2-fluoroalkylated 3-(alpha-cyanobenzy-lated) indoles were accessed with excellent enantioselectivity and good yields. Mechanistic studies revealed a negative nonlinear effect which explained the stereochemical outcome. The enantioenriched 3-(alpha-cyanobenzylated) indoles demonstrated scalability and potential utility as hubs for chiral tryptamines, indole-3-acetic acid derivatives, and triarylmethanes, and a formal synthesis of a natural product analogue was disclosed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Zhe Wang, Nick Wierich, Jingjing Zhang, Constantin G. Daniliuc, Armido Studer
Summary: In this study, a method for direct generation of alkyl radicals from alkylboronic pinacol esters (APEs) through reaction with aminyl radicals is reported. Aminyl radicals are readily generated by visible-light-induced homolytic cleavage of the N-N bond in N-nitrosamines, and C radical generation occurs through nucleohomolytic substitution at boron. As an application, the highly efficient photochemical radical alkyloximation of alkenes with APEs and N-nitrosamines under mild conditions is presented. Various primary, secondary, and tertiary APEs can be used in this scalable transformation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Roman Kleinmans, Subhabrata Dutta, Kristers Ozols, Huiling Shao, Felix Schafer, Rebecca E. Thielemann, Hok Tsun Chan, Constantin G. Daniliuc, Kendall N. Houk, Frank Glorius
Summary: The ortho-selective intermolecular photocycloaddition of bicyclic aza-arenes is reported, utilizing a strain-release approach. This reaction enables the construction of C-(sp(3))-rich bicyclo-[2.1.1]-hexanes directly connected to N-heteroarenes. Photophysical experiments and DFT calculations reveal the mechanism of this selective intermolecular photocycloaddition.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biochemistry & Molecular Biology
Dietrich Pueschel, Simon Hede, Ivan Maisuls, Simon-Patrick Hoefert, Dennis Woschko, Ralf Kuehnemuth, Suren Felekyan, Claus A. M. Seidel, Constantin Czekelius, Oliver Weingart, Cristian A. A. Strassert, Christoph Janiak
Summary: The incorporation of flavin derivatives in metal-organic frameworks (MOFs) enhances the rigidity and stability of the materials, leading to increased fluorescence lifetime and quantum yield.
Article
Chemistry, Physical
Jonas Elfert, Anup Bhunia, Constantin G. Daniliuc, Armido Studer
Summary: In this study, a radical transformation that enables intramolecular oxygen atom transfer to alkenes using the nitro functionality in nitroarenes as an oxygen donor is disclosed. The reaction proceeds via iron-catalyzed metal hydrogen atom transfer to alkenes and subsequent oxygenation, resulting in alkene hydration. Compared to intermolecular radical oxygenation, the intramolecular variant offers advantages, particularly in terms of diastereoselective radical hydration of conformationally flexible alkenes. The aryl moiety connecting the reactive NO2-functionality to the alkene substrate can be cleaved after oxygen transfer, yielding products derived from a formal diastereoselective intermolecular alkene hydration. Additionally, the resulting aniline entity after oxygen transfer can be used for the construction of nitrogen-containing heterocycles.
Article
Biochemistry & Molecular Biology
Simon T. Steiner, Ivan Maisuls, Anna Junker, Gunter Fritz, Andreas Faust, Cristian A. Strassert
Summary: A thorough understanding of the photophysical properties of fluorescent labels is essential for their reliable and predictable performance in biological applications. In this study, four fluorescent S100A9-targeting compounds were characterized in terms of their UV-vis absorption and photoluminescence spectroscopy, fluorescence quantum yields, excited state lifetimes, and rate constants. The effect of conjugation with the targeting structure and protein binding on the photophysical properties of the probes was investigated. The findings provide insights into the potential applications of these compounds in inflammation imaging and fluorescence assay developments, while highlighting the importance of preliminary photophysical screening.
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
(2023)
Article
Chemistry, Organic
Shyam Kumar Banjare, Dirk Leifert, Frauke Weidlich, Constantin G. Daniliuc, Fatmah A. Alasmary, Armido Studer
Summary: An oxidative radical cascade addition cyclization approach using eco-friendly iron catalysis and inexpensive TBHP as the oxidant has been developed for the synthesis of quinoline-based p-extended polyheterocyclic compounds. This method allows the preparation of quinolines that are p-conjugated with an additional heteroarene moiety in a single sequence.
Article
Chemistry, Multidisciplinary
Anirban Maity, Armido Studer
Summary: 1,2-Aminoxyalkylation of alkenes with alkyl iodides and TEMPONa in the presence of an aryldiazonium salt as an XAT mediator is described. Primary, secondary and tertiary alkyl iodides can serve as C-radical precursors in the 1,2-aminoxyalkylation reaction with electrophilic alkenes. The resulting alkoxyamines can be easily converted to alcohols or ketones through reduction or oxidation, respectively. Mechanistic studies reveal the involvement of aryl radicals generated through SET-reduction of the aryldiazonium salt in the XAT process, allowing the addition of alkyl radicals to alkenes. The trapping of the adduct radicals with TEMPO leads to the formation of 1,2-aminoxyalkylation products. Transition metals are not required for these mild conditions transformations. Direct 1,2-aminoxyperfluoroalkylation of alkenes with perfluoroalkyl halides can be achieved using TEMPONa without the need for an aryldiazonium salt as an XAT mediator.
Article
Chemistry, Multidisciplinary
Till Drennhaus, Dirk Leifert, Jessika Lammert, Jan Philipp Drennhaus, Klaus Bergander, Constantin G. Daniliuc, Armido Studer
Summary: Enantioenriched chiral indoles were synthesized through a mild and efficient radical cascade reaction. The targeted indoles were accessed by stereochemical control using a chiral copper-bisoxazoline complex. The method demonstrated excellent enantioselectivity and good yields, and the mechanism was elucidated through mechanistic studies.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Angela Mesias-Salazar, Rene S. Rojas, Fernando Carrillo-Hermosilla, Javier Martinez, Antonio Antinolo, Oleksandra S. Trofymchuk, Fabiane M. Nachtigall, Leonardo S. Santos, Constantin G. Daniliuc
Summary: This study presents the synthesis and characterization of a new family of one-component catalysts based on guanidinium salts, which are used for the synthesis of cyclic carbonates. The results demonstrate that these catalysts have good conversion rates and can operate effectively at moderate pressures and temperatures.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Timo Stuenkel, Kathrin Siebold, Daichi Okumatsu, Kazuki Murata, Louise Ruyet, Constantin G. Daniliuc, Ryan Gilmour
Summary: The regio- and enantio-selective dearomatization of phenols has been achieved using I(i)/I(iii) catalysis enabled fluorination. The reaction is highly selective and efficient, offering great potential in the field of hydroxylation chemistry.
Article
Chemistry, Organic
Tobias Winge, Dirk Schepmann, Judith Schmidt, Constantin Daniliuc, Ernst-Ulrich Wuerthwein, Bernhard Wuensch
Summary: Spirocyclic scaffolds are important in drug discovery as they enhance specific interactions with protein binding sites. This study synthesized a series of spirocyclic compounds and found that one of them exhibited favorable pharmacological and physicochemical properties.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
