Article
Chemistry, Multidisciplinary
Rui Chang, Yubing Pang, Juntao Ye
Summary: This study reports a photoinduced approach for hydroarylation of unactivated olefins using 4-hydroxycoumarins as the arylating reagent. The key to the success of this reaction is the conversion of nucleophilic 4-hydroxycoumarins into electrophilic carbon radicals through photocatalytic arene oxidation. This method not only overcomes the polarity-mismatch issue encountered under ionic conditions but also allows for a broad substrate scope and inhibits side reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tsukasa Tawatari, Ritsuki Kato, Riku Kudo, Kiyosei Takasu, Hiroshi Takikawa
Summary: In this study, we report on the intramolecular (3+2) cycloaddition reactions between ynamides and benzyne. These reactions involve the formation of two bonds and are facilitated by using benzyne precursors containing a chlorosilyl group. The intermediate indolium ylide in these reactions exhibits both nucleophilic and electrophilic properties at its C2 atom.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Jordan L. Harper, Stephanie Felten, Ryan M. Stolley, Alexander S. Hegg, Paul H-Y Cheong, Janis Louie
Summary: The mechanistic investigation into the origins of regio- and chemoselectivities observed in iron/pyridine dialdimine (PDAI)-catalyzed intermolecular [2+2+2] cycloaddition reactions of terminal alkynes and cyanamides reveals the significant role of the hemilabile PDAI ligand in controlling the observed selectivity of the resultant products.
Article
Chemistry, Multidisciplinary
Ming Zhang, Xiao-Chen Wang
Summary: This method presents a mild and efficient approach for synthesizing enantioenriched tetrahydroquinoline-fused cyclobutenes through a cascade reaction, catalyzed by chiral spiro-bicyclic bisboranes. The bisboranes function by catalyzing hydride transfer and activating the alkynone substrate for an enantioselective cycloaddition reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Rayhane Hammami, Pascale Maldivi, Christian Philouze, Sebastien Carret, Benjamin Darses, Soufiane Touil, Jean-Francois Poisson
Summary: A variety of 4-phosphinylpyrrolidin-3-ones were synthesized via a [3+2] cycloaddition reaction between aryl aldonitrones and phosphinylallenes. The products were obtained as unique 4,5-trans diastereomers in yields ranging from 47% to 80% for 23 examples. Chiral racemic allenes exhibited a moderate 2:1 to 4:1 2,5-diastereoselectivity. Under the reaction conditions, the cycloadducts undergo a rearrangement to selectively afford the corresponding pyrrolidin-3-ones. DFT calculations provided insights into the mechanism involving the homolytic cleavage of the N-O bond of the cycloadduct.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Shi-Yi Zhuang, Jin-Yi Liu, Hui Guo, Yong-Xing Tang, Xiang-Long Chen, Jin-Tian Ma, Yan-Dong Wu, An-Xin Wu, Kai-Lu Zheng
Summary: A metal-free multicomponent cascade annulation reaction using an I2-DMSO mediator has been developed, which involves trifunctionalization of the substrate and cleavage of bonds to obtain pyrrolo[2,1-a]isoquinoline derivatives with a quaternary carbon center.
Article
Chemistry, Multidisciplinary
Argha Saha, Chiranjit Sen, Srimanta Guin, Chandan Das, Debajit Maiti, Subhabrata Sen, Debabrata Maiti
Summary: We have developed a photoinduced protocol for the synthesis of pharmaceutically important oxazole molecules using diazo- and nitrile-containing reactants. The process involves the initial photolysis of the diazo compound to afford singlet carbenes, which are tapped by nitriles in a [3+2] cycloaddition fashion to give substituted oxazoles. The protocol is applicable for the synthesis of diverse oxazoles and can be used for drug synthesis and isotope labeling.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Romain Losa, Charlotte Lorton, Pascal Retailleau, Jeirome Bignon, Arnaud Voituriez
Summary: An efficient and straightforward method for synthesizing polyfunctionalized 2-azetines was developed using a phosphine-promoted tandemaza-Michael addition/intramolecular Wittig reaction. The synthesis was made catalytic by reducing the phosphine oxide with phenylsilane. Various post-transformation steps, including a novel [2 + 2] photodimerization, were demonstrated. Preliminary biological tests showed that these fluorinated 1,2-dihydroazete-2,3-dicarboxylates exhibited significant cytotoxicity against human tumor cell lines.
Article
Biochemistry & Molecular Biology
Igor Philippov, Yuriy Gatilov, Alina Sonina, Aleksey Vorob'ev
Summary: A method for the synthesis of pyrazolo[1,5-a]pyridine-3-ylphosphonates by oxidative [3+2]cycloaddition reaction was reported. Different substituents have an effect on the reaction activity, with 4-halogenated substituents showing lower reactivity.
Article
Chemistry, Multidisciplinary
Nicolaj Inunnguaq Jessen, Maksimilian Bura, Giulio Bertuzzi, Karl Anker Jorgensen
Summary: An efficient and stereoselective synthesis of chiral cycl[3.2.2]azines has been achieved through the rational design and utilization of novel (E)-3-benzylidene-3H-pyrrolizines in iminium-ion catalysis. The method allows for incorporation of diverse enals and the obtained products can undergo selective transformations while retaining stereochemical information established in the [8+2] cycloaddition.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Peter Wonneberger, Nils Koenig, Menyhart B. Sarosi, Evamarie Hey-Hawkins
Summary: Reduction of 1-phospha-2-azanorbornene derivative leads to formation of a novel compound 1-phosphabicyclo[3.2.1]octa-2,5-diene and an unusual 2H-phosphole dimer. Additionally, 3H-phospholes were found to potentially act as dienophile in the dimerisation reaction under elevated temperatures, contrary to previous assumptions of their synthetic irrelevance.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Yongxiang Zheng, Anna Perfetto, Davide Luise, Ilaria Ciofini, Laurence Miesch
Summary: The research demonstrates the use of difluorinated diazoacetone as a practical reagent for the direct synthesis of CF2H-substituted 2-amidofurans. These newly designed amidofurans were further developed to create new nitrogen-containing frameworks that may be challenging to obtain otherwise.
Article
Chemistry, Applied
Ping Chen, Wei Cao, Xiangqian Li, Dayong Shi
Summary: This study presents a method for synthesizing polysubstituted five-membered heterocycles, resulting in a variety of polysubstituted furans, thiophenes, and pyrroles. The method is efficient, atom economical, and the products can be used to synthesize other useful compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Lei Li, William L. Turnbull, Robert McDonald, F. G. West
Summary: 3-Acyl-4-hydroxypyan-2-ones with pendent furans, synthesized from dehydroacetic acid, undergo intramolecular [4+4]-photocycloaddition to yield lactone-bridged cyclooctenones with complete diastereoselectivity, showing good efficiency in THF at 0 degrees C with stoichiometric lithium base present.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Tao Wang, Bo Huang, You-Qing Wang
Summary: Using chiral phosphoric acids as organocatalysts, a formal asymmetric (4+2) cycloaddition of 3-methylene isoindolinone and in situ-generated ortho-quinone methide substrates is achieved. This reaction allows the construction of spiro chroman-isoindolinones containing spiro-N,O-heterocycles with high enantioselectivity, with a broad substrate scope.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Puthan Veetil Muhasina, Pattiyil Parameswaran
Summary: This study investigates the stability, bonding and reactivity of a series of compounds consisting of an electron-donor group and an electron-donor ligand, with non-bonding electrons. The ground states of these compounds are found to have a central carbon atom with a lone pair of electrons and an unpaired electron. The spin transition from pi- to sigma-type orbitals is observed as the pi-acceptor strength of the donor ligand increases.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ramapada Dolai, Rahul Kumar, Benedict J. Elvers, Pradeep Kumar Pal, Benson Joseph, Rina Sikari, Mithilesh Kumar Nayak, Avijit Maiti, Tejender Singh, Nicolas Chrysochos, Arumugam Jayaraman, Ivo Krummenacher, Jagannath Mondal, U. Deva Priyakumar, Holger Braunschweig, Cem B. Yildiz, Carola Schulzke, Anukul Jana
Summary: A new type of carbodicarbene (CDC) with two different classes of carbenes has been reported, which shows promising potential as organic electron donors and n-dopants. These compounds exhibit notable redox properties and can form carbon-carbon sigma bonds through reactions with [NO][SbF6].
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Diana Mathew, Pattiyil Parameswaran
Summary: In this study, meso-aryl BODIPYs were designed as a structural motif for the transformation from aggregation-caused quenching (ACQ) to aggregation-induced emission (AIE). A series of meso-aryl BODIPY derivatives were synthesized and their photophysical properties were analyzed. The emission properties were found to be correlated with the flexibility of the aromatic ring. Decorating BODIPYs with polycyclic aromatic systems inhibited pi-pi stacking and allowed for the conversion of planar aryl luminophores from ACQ to AIEgens. The meso-pyrene BODIPY derivative also exhibited excellent mechanofluorochromic behavior.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Mohd Nazish, Christina M. M. Legendre, Yi Ding, Bastian Schluschass, Brigitte Schwederski, Regine Herbst-Irmer, Parameswaran Parvathy, Pattiyil Parameswaran, Dietmar Stalke, Wolfgang Kaim, Herbert W. W. Roesky
Summary: A successful selective reduction of X2B-Tip (Tip= 1,3,5-Pr- i (3)-C6H2, X = I, Br) with KC8 and Mg metal, respectively,in the presence of a hybrid ligand (C6H4(PPh2)LSi) leads to a stable low-valent five-membered ring as a boryl radical [C6H4(PPh2)LSiBTip][Br](1) and neutral borylene [C6H4(PPh2)LSiBTip] (2). Compound 2 reacts with 1,4-cyclohexadiene, resulting in hydrogen abstraction to afford the radical [C6H4(PPh2)LSiB(H)Tip](3). Quantum chemical studies reveal that compound 1 is a B-centered radical, and compound 2 is a phosphane and silylene stabilized neutral borylene in a trigonal planar environment, whereas compound 3 is an amidinate-centered radical. Although compounds 1 and 2 are stabilized by hyperconjugation and pi-conjugation, they display high H-abstraction energy and basicity, respectively.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Mohd Nazish, Christina M. Legendre, Nico Graw, Regine Herbst-Irmer, Shahila Muhammed, Pattiyil Parameswaran, Dietmar Stalke, Herbert W. Roesky
Summary: This study presents a method for preparing chain-type unsaturated molecules with low oxidation state Si(I) and Sb(I), and their characteristics of sigma-type lone pairs and pseudo-pi bonds are investigated. The formation of the pseudo-pi bond is through the hyperconjugative transfer of the pi-type lone pair at Sb to the Si-N sigma* MO.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Sneha Parambath, Vishnu Thannimangalath, Pattiyil Parameswaran
Summary: The structure, chemical bonding, and reactivity of neutral 16 valence electrons transition metal complexes of beryllium were studied. Dative quadruple bonds between the transition metal and beryllium were observed, with the strength varying based on the ligands coordinated to the transition metal. The beryllium center showed ambiphilic reactivity due to the M-Be dative quadruple bonds, as indicated by high proton and hydride affinity values.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Organic
Siva Sankar Murthy Bandaru, Carola Schulzke
Summary: The novel organic salt was synthesized through a Lewis acid and Lewis-base reaction and analyzed by various spectroscopic and crystallographic techniques.
Article
Chemistry, Inorganic & Nuclear
Siva Sankar Murthy Bandaru, Claudia Schindler, Felix Wenzek, Carola Schulzke
Summary: Several synthetic cross-coupling procedures were evaluated for tethering pyrazine to dithiocarbonates. The resulting compounds can serve as pro-ligands and can be converted into ene-dithiolate ligand systems resembling molybdopterin by removing the C=O moiety. The coupling of 2-iodopyrazine with stannylated dithiocarbonate units mediated by copper(I)-thiophene-2-carboxylate in stoichiometric equivalents proved to be the most efficient and reliable method for synthesizing the targeted compounds.
Article
Chemistry, Multidisciplinary
Priyanka Saha, Nicolas Chrysochos, Benedict J. Elvers, Sebastian Paetsch, Sk Imraj Uddin, Ivo Krummenacher, Muneshwar Nandeshwar, Anshika Mishra, Karthik V. Raman, Gopalan Rajaraman, Ganesan Prabusankar, Holger Braunschweig, Prince Ravat, Carola Schulzke, Anukul Jana
Summary: A modular approach for the synthesis of isolable crystalline Schlenk hydrocarbon diradicals from m-phenylene bridged electron-rich bis-triazaalkenes as synthons is demonstrated. The diradical nature and triplet electronic structure of the synthesized compounds are confirmed through EPR spectroscopy and computational analysis. The potential of the modular methodology is further illustrated through the utilization of 4,6-dimethyl-m-phenylene as a coupling unit.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Medicinal
Martin Napierkowski, Una Janke, Alena Rong, Mihaela Delcea, Siva Sankar M. Bandaru, Carola Schulzke, Patrick J. Bednarski
Summary: In recent years, the biological properties of pentathiepins have gained attention for their potential in cancer treatment. However, their low solubility and stability limitations have hindered biological evaluation. This study investigated the use of liposomes as drug carriers for pentathiepins to improve solubility and stability. The results showed that the aqueous solubility of pentathiepins increased significantly when incorporated into liposomes, and the stability of pentathiepins in the presence of the antioxidant glutathione was enhanced. Moreover, the liposomal loaded pentathiepins demonstrated comparable anticancer activity to free pentathiepins. In conclusion, liposomes are a suitable carrier for pentathiepins and can improve their solubility and stability without compromising their anticancer activity.
ARCHIV DER PHARMAZIE
(2023)
Article
Chemistry, Physical
Rinsha Cholasseri, Pattiyil Parameswaran
Summary: Locked azobenzenes (LAB) derivatives are studied for their thermodynamic stability and vertical excitation energy in the presence of tetraethyl ammonium ion (TEA) substituent and KcsA K+-ion channel protein environment. It is found that the Z-isomer is more thermodynamically stable than the E-isomer. The substitution of tetraethyl ammonium ion does not affect the thermodynamic stability, but it is reversed in the protein environment. The photochemistry of LAB is unaffected by para-substituted TEA, but the geometrical changes imposed by the protein decrease the vertical excitation energy.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2023)
Article
Chemistry, Organic
S. Shurooque Kanneth, Diana Mathew, Pattiyil Parameswaran, Anjali K. Sajeev, K. N. Narayanan Unni, Lakshmi Chakkumkumarath
Summary: Structurally simple and synthetically straightforward molecules based on 1,4-dihydropyridine (DHP) have been studied for their unique photophysical properties. By introducing different substituents, such as electron-withdrawing groups and alkyl or alkylaryl groups, on the periphery of DHP, interesting photophysical properties like negative solvatochromism and aggregation-induced emission (AIE) can be achieved. Additionally, variations in molecular packing in the crystal lattice contribute to the tuning of solid-state emission properties. The aggregates of these molecules are effective in detecting aromatic volatile organic compounds (VOCs), with p-xylene showing a significant enhancement in emission.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Benedict J. Elvers, Sebastian Paetsch, Siva S. M. Bandaru, Vera Krewald, Carola Schulzke, Christian Fischer
Summary: Heteroleptic molybdenum complexes with P2N2 and non-innocent dithiolene ligands were synthesized and electrochemically characterized. The reduction potentials of the complexes were adjusted by ligand-ligand cooperativity via non-covalent interactions. This finding was supported by electrochemical studies, UV/Vis spectroscopy, and temperature-dependent NMR spectroscopy. The observed behavior resembles enzymatic redox modulation through second ligand sphere effects.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Mithilesh Kumar Nayak, Benedict J. Elvers, Debdeep Mandal, Ayan Das, Raghunathan Ramakrishnan, Kaustubh R. Mote, Carola Schulzke, Cem Burak Yildiz, Anukul Jana
Summary: The reduction of 2-H-substituted pyrrolinium cations results in dimerisation or H-abstracted products, depending on the N-substituents. The dimerised 2,2'-bipyrrolidine derivatives with a central carbon-carbon single bond are stable and can be oxidised chemically or electrochemically. These dimers, which are air and moisture-stable, can serve as a source of two electrons in various chemical transformations.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Nicolas Chrysochos, Sebastian Paetsch, Benedict J. Elvers, Ivo Krummenacher, Muneshwar Nandeshwar, Ganesan Prabusankar, Holger Braunschweig, Carola Schulzke, Prince Ravat, Anukul Jana
Summary: The synthesis of a twisted, push-pull, and electron-rich alkene is reported, providing a unique combination for alkene compounds. This newly synthesized alkene motif was used as a donor for the synthesis of a boron-containing pi-conjugated compound with zwitterionic properties through intramolecular charge transfer.
CHEMICAL COMMUNICATIONS
(2023)