Article
Chemistry, Organic
Honghua Zuo, Hendrik F. T. Klare, Martin Oestreich
Summary: A catalytic silylium-ion-promoted intramolecular alkyne carbosilylation reaction is reported, involving electrophilic activation of the C-C triple bond by a silylium ion and maintenance of the catalytic cycle through protodesilylation of an allylsilane reagent. The reaction exhibits exclusive 7-endo-dig selectivity and results in fully substituted vinylsilane derivatives of silylated benzocycloheptenes. Control experiments demonstrate that the catalytically active silylium ion can be regenerated by protodesilylation of the vinylsilane product.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Suresh Kanikarapu, Manash Protim Gogoi, Shubham Dutta, Akhila K. Sahoo
Summary: This study presents a straightforward and selective intramolecular cyclization reaction for the synthesis of diverse compounds. The reaction exhibits broad functional group compatibility, leading to improved synthetic efficiency and yield of the products.
Article
Chemistry, Applied
Tales A. C. Goulart, Ana M. S. Recchi, Davi F. Back, Gilson Zeni
Summary: The Lewis acid-promoted cyclization reaction of benzomidazole thiols with propargyl alcohols for the selective synthesis of benzoimidazolo thiazines and benzothiazolo imidazoles is described. The reaction is regioselective and controlled by the choice of solvent. The best reaction conditions were determined through systematic study, resulting in the formation of six-membered benzoimidazolo thiazines using boron trifluoride etherate and dichloromethane as the solvent, and five-membered benzothiazolo imidazoles using the same starting material and reagents with dimethylformamide as the solvent. The proposed mechanism of the cyclization reaction is based on experimental results and control experiments.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Anna E. Vartanova, Andrey Yu Plodukhin, Nina K. Ratmanova, Ivan A. Andreev, Mikhail N. Anisimov, Nikita B. Gudimchuk, Victor B. Rybakov, Irina I. Levina, Olga A. Ivanova, Igor Trushkov, Igor Alabugin
Summary: This study expands the limits of endo-tet cyclizations by showing that donor-acceptor cyclopropanes can form a seven-membered ring via a genuine 6-endo-tet process, yielding tetrahydrobenz[b]azepin-2-ones. Control of the stereochemistry of the products through reaction conditions allows access to both diastereomers.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Roberto do Carmo Pinheiro, Luiz Eduardo Welter, Bernardo A. Iglesias, Davi F. Back, Luiza Souza Marques, Cristina Wayne Nogueira, Gilson Zeni
Summary: Heterocycles fused to seven-membered rings were synthesized in a highly selective manner using potassium tert-butoxide-catalyzed one-pot cyclization. Systematic study revealed that a catalytic amount of potassium tert-butoxide, dimethyl sulfoxide, and the tert-BuOK/tert-BuOH equilibrium played crucial roles in the formation of products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yi-En Liang, Ming-Yiang Chang, Hsi Ho, Chun-Tang Chiou, Balaji D. Barve, Wen-Tai Li
Summary: A novel cascade reaction utilizing Pd-(II) catalysis was developed for the synthesis of fused oxatricyclic compounds from 2-benzyl-3-alkynyl chromones and activated/unactivated alkenes. This concise one-pot synthetic approach offers potential in difunctionalizing unbiased alkynes based on 2-benzyl-3-(alkynyl)-4H-chromen-4-one via O-attack endo-dig cycloisomerization followed by olefination with both activated and unactivated alkenes.
Article
Chemistry, Applied
Peng Ma, Jianhui Wang, Guiyan Liu
Summary: In this paper, a simple method for the synthesis of substituted 1-naphthylamines is described. The method involves a Cu(I) catalytic system in water, avoiding competitive reactions and allowing for the rapid synthesis of a diverse compound library. Gram-scale synthesis and mechanism studies further demonstrate the synthetic potential and reaction process of this method.
APPLIED ORGANOMETALLIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yingjian Ren, Zhanglang Zhou, Weinan Chen, Si Liu, Min Wang, Gang Zhou
Summary: In this study, unexpected 6-endo-dig and ring-expansion cycloisomerizations were discovered for ortho-disubstituted thiophene derivatives with 1-en-3-yne moieties in the presence of PtCl2. The reaction pathway was found to be determined by the substrate structure. A benzo[b]thiophene derivative was obtained through a 6-endo-dig cyclization with a [1,2]-alkyl shift when the CvC double bond belonged to an aromatic ring, while a ring-expansion cyclization reaction occurred when the double bond came from an aliphatic alkene, resulting in a cyclopenta[c]thiapyran analogue. The proposed mechanisms of both reactions were verified by density functional theory calculations.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Mou Mandal, Renuka Pradhan, Upakarasamy Lourderaj, Rengarajan Balamurugan
Summary: A direct ring-closing strategy using vinylogous amides under gold catalysis has been developed to synthesize benzo[b]azepines, overcoming the traditional 5-endo-dig cyclization. Deuterium scrambling experiments and DFT studies support a reaction mechanism involving a stabilizing conformational change of a seven-membered vinyl gold intermediate through a key cyclopropyl gold carbene intermediate and subsequent protodeauration mediated by the counter anion.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Abdulkader Baroudi, Khaled Jaradat, Amir Karton
Summary: The cyclization reactions of hex-5-yn-1-yl radical systems with different linkers were investigated, and it was found that B, Si, P, S, Ge, As, and Se linkers prefer 6-endo-dig cyclization. This research provides fundamental insights into the rational synthetic design of cyclic compounds and a new tool for cyclization preference prediction.
Correction
Chemistry, Multidisciplinary
Hassan Seyrani, Sorour Ramezanpour, Aref Vaezghaemi, Farzad Kobarfard
Summary: The correction presents a novel reaction sequence for the selective synthesis of saccharin substituted 2,5-dihydropyrroles via sequential Ugi-Smiles reaction and transition-metal-free endo-dig Conia-ene cyclization.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Gottam Sreenivasulu, Veerabhushanam Kadiyala, Chittala Emmaniel Raju, Balasubramanian Sridhar, Galla Karunakar
Summary: An efficient gold-catalyzed synthesis of pyrazolo[1,5-a]pyridines has been developed from pyrazolo substituted propargyl alcohols via 6-endo-dig cyclization. In this intramolecular cyclization reaction, a new C-N bond was regioselectively formed, and good to excellent yields of pyrazolo[1,5-a]pyridines were obtained in one-pot.
Article
Chemistry, Multidisciplinary
Purnachandar Dalovai, Galla Venkata Karunakar, Vidya Damodaran Nadar, Venkata Ramana Doddi, Suneel Kanaparthy
Summary: An efficient synthetic method for accessing substituted aminobenzophenones has been developed, catalyzed by gold and forming a new C-C bond through intramolecular 6-endo-dig cyclization. The substituted aminobenzophenones were obtained in good to excellent yields.
JOURNAL OF CHEMICAL SCIENCES
(2021)
Article
Chemistry, Multidisciplinary
Vembu Yogeshwaran, Senthilkumar Dhayanithi, Periasamy Vinoth Kumar, Selvaraj Mohana Roopan
Summary: This article introduces the importance of organic ring closure reactions of acyclic compounds and the application of the Baldwin rule in these reactions. In particular, the Baldwin rule favors the use of sp-geometric molecules in cyclization reactions, and the significance of endo-dig cyclization reactions in the synthesis of various compounds is discussed.
RESULTS IN CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jiayue Fu, Bingbing Li, Xiugui Wang, Qida Liang, Xiaoshi Peng, Lu Yang, Tao Wan, Xinxiu Wang, Bin Lin, Maosheng Cheng, Yongxiang Liu
Summary: In this study, a gold(I)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines. The functional group tolerance of this cyclization was systematically examined, and a possible mechanism was proposed. Derivatization of 2-(naphthalen-2-yl)aniline was carried out to access benzo[alpha]carbazole, benzo[c,h]cinnoline and dibenzo[i]phenanthridine derivatives in a divergent manner.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Analytical
Ion Ghiviriga
Summary: Water solubility measurements are essential in drug discovery, toxicological or environmental studies, and industrial processes. We developed an automated NMR method that provides accurate results with a wide solubility range, and it is faster than the traditional shake-flask method. By analyzing saturated solutions with excess solute, the NMR spectra can distinguish between dissolved and dispersed liquids. Evaluation of the method's selectivity, accuracy, precision, and limit of quantitation is presented.
ANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Alafate Adili, John-Paul Webster, Chenfei Zhao, Sharath Chandra Mallojjala, Moises A. Romero-Reyes, Ion Ghiviriga, Khalil A. Abboud, Mathew J. Vetticatt, Daniel Seidel
Summary: The enantioselective oxa-Pictet-Spengler reactions of tryptophol with aldehydes were successfully conducted under weakly acidic conditions using a combination of indoline HCl salt and bisthiourea compound as catalysts. Mechanistic investigations determined the roles of both catalysts and confirmed the involvement of oxocarbenium ion intermediates, ruling out alternative scenarios. A stereochemical model derived from density functional theory calculations provided the basis for the development of a highly enantioselective stereodivergent variant with racemic tryptophol derivatives.
Article
Chemistry, Organic
Quintin Elliott, Igor V. Alabugin
Summary: AIBN is a convenient electrophilic cyanation reagent that can convert ArLi into ArCN under mild conditions. The addition/fragmentation cascade is controlled by Li...N chelation, with AIBN nitrogens assisting in the nearly barrierless fragmentation into the desired ArCN product. Acidic C-H bonds in the fragmented byproduct consume ArLi through protonation. Density functional theory calculations and isotopic labeling were used to study the mechanism and explain the switch to substituted hydrazones in reactions with BuLi.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Almir. S. S. Gazizov, Andrey. V. V. Smolobochkin, Tanzilya. S. S. Rizbayeva, Sergey. Z. Z. Vatsadze, Alexander. R. R. Burilov, Oleg. G. G. Sinyashin, Igor. V. V. Alabugin
Summary: Ureas are often considered to have similar reactivity as amides due to their structural similarity, but they can exhibit distinct differences in reactivity. Rotation of ureas can switch off the amide resonance and recover the nucleophilicity of one of the nitrogen atoms. This change in reactivity is an example of stereoelectronic deprotection and can be used for the synthesis of unusual compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Sara E. E. Kearney, Anghelo J. J. Gangano, Daniel G. G. Barrus, Kyle J. J. Rehrauer, Terry-Elinor R. Reid, Primali V. V. Navaratne, Emily K. K. Tracy, Adrian Roitberg, Ion Ghiviriga, Christopher W. W. Cunningham, Thomas Gamage, Alexander J. J. Grenning
Summary: The resorcinol-terpene phytocannabinoid template is a privileged scaffold for developing therapeutics targeting the endocannabinoid system. Axially chiral cannabinols (axCBNs) and axially chiral cannabidiols (axCBDs), inspired by cannabidiol (CBD), are unique structural modifications that enhance the physical and biological properties of cannabinoid ligands. These findings provide a promising direction for the design of novel cannabinoid ligands for drug discovery and exploration of the complex endocannabinoid system.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Vera A. Vil', Yana A. Barsegyan, Leah Kuhn, Alexander O. Terent'ev, Igor V. Alabugin
Summary: The reaction of Ni(II) acetate with diacyl peroxides produces high-valence Ni-species capable of catalytic oxidative acyloxylation of C(sp3)-H bonds in ethers, ketones, and alkanes. The desired esters were obtained in 20-82% yields. Computational and experimental analyses revealed various viable C-H activation patterns, with the spirocyclopropyl moiety playing a crucial role in preventing premature radical decarboxylation.
Article
Chemistry, Inorganic & Nuclear
Vineet K. Jakhar, Yu-Hsuan Shen, Sung-Min Hyun, Alec M. Esper, Ion Ghiviriga, Khalil A. Abboud, Daniel W. Lester, Adam S. Veige
Summary: This article presents an easier, safer, and scalable approach to synthesize a trianionic pincer ligand and its use in preparing a Mo cyclic polymer catalyst. The synthesis method allows for scaling up, reducing the main barrier to accessing cyclic polymer catalysts. It also enables derivatization of the C-ipso carbon of the pincer's central ring for various modifications. The activity of complex 7 in the polymerization of phenylacetylene was confirmed through gel permeation chromatography, dynamic light scattering, and intrinsic viscosity measurements.
Article
Chemistry, Applied
Ivan A. Yaremenko, Yulia Yu. Belyakova, Arina A. Demina, Peter S. Radulov, Igor V. Alabugin, Alexander O. Terent'ev
Summary: A selective reaction between bridged ozonides and Fe(II) salts has been found to proceed through O-O and C-C scissions and halogenation, leading to the formation of alpha-halogen substituted delta-ketoesters and delta-diketones in yields of 15-72%. This overall sequence demonstrates how a temporary peroxide functionality can be used to replace the acyl group within an acetoacetic ester unit with a halogen.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Biochemistry & Molecular Biology
Andrei V. Bogdanov, Margarita Neganova, Alexandra Voloshina, Anna Lyubina, Syumbelya Amerhanova, Igor A. Litvinov, Olga Tsivileva, Nurgali Akylbekov, Rakhmetulla Zhapparbergenov, Zulfiia Valiullina, Alexandr V. Samorodov, Igor Alabugin
Summary: A series of new fluorinated isatins were synthesized via a simple one-pot procedure. These new isatins exhibit antitumor activity, anti-aggregation activity, and antagonistic effect against plant pathogens.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Biochemistry & Molecular Biology
Elmira Gibadullina, Margarita Neganova, Yulia Aleksandrova, Hoang Bao Tran Nguyen, Alexandra Voloshina, Mikhail Khrizanforov, Thi Thu Nguyen, Ekaterina Vinyukova, Konstantin Volcho, Dmitry Tsypyshev, Anna Lyubina, Syumbelya Amerhanova, Anna Strelnik, Julia Voronina, Daut Islamov, Rakhmetulla Zhapparbergenov, Nurbol Appazov, Beauty Chabuka, Kimberley Christopher, Alexander Burilov, Nariman Salakhutdinov, Oleg Sinyashin, Igor Alabugin
Summary: This study explores the biological activity of a family of new hybrid molecules that combine sterically hindered phenols (SHPs) with additional urea/thiourea fragments. It finds that these compounds exhibit cytotoxic activity against tumor cells and have dual properties of pronounced antioxidant activity and increased reactive oxygen species generation. Molecular docking analysis reveals a potential target for these compounds. The most promising compounds can induce apoptosis in cancer cells through the intrinsic mitochondrial pathway.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Organic
Ivan A. Yaremenko, Yulia Yu. Belyakova, Peter S. Radulov, Michael G. Medvedev, Nikolai V. Krivoshchapov, Igor V. Alabugin, Alexander O. Terent'ev
Summary: The relief of stereoelectronic frustration drives the acid-catalyzed three-component condensation, allowing the preparation of otherwise inaccessible compounds rapidly and selectively.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Beauty K. Chabuka, Igor V. Alabugin
Summary: In order to use holes as catalysts, the oxidation potential along the reaction path must increase, leading to hole upconversion. This study provides guidelines for the rational design of hole-catalyzed Diels-Alder (DA) reactions. The occurrence and magnitude of hole upconversion depend strongly on the placement and nature of substituents in the reactants, and stereoelectronic effects can activate or deactivate upconversion via conformational changes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biochemistry & Molecular Biology
Elena Chugunova, Almir S. Gazizov, Daut Islamov, Victoria Matveeva, Alexander Burilov, Nurgali Akylbekov, Alexey Dobrynin, Rakhmetulla Zhapparbergenov, Nurbol Appazov, Beauty K. Chabuka, Kimberley Christopher, Daria I. Tonkoglazova, Igor V. Alabugin
Summary: This study reports an unusual transformation in which the transient formation of a nitrene moiety initiates a sequence of steps leading to remote oxidative C-H functionalization and nitrene reduction into an amino group. No external oxidants or reductants are required for this process, and detected intermediates and computational analysis suggest the involvement of pyrazole ring opening and recyclization.
Article
Biochemistry & Molecular Biology
Adam Campbell, Nikolas R. Dos Santos, Igor Alabugin
Summary: We utilized a cycloaromatization reaction to photouncage aldehydes and ketones by relieving excited state antiaromaticity. Several synthetic routes were developed to prepare photocaged carbonyls as allylically substituted 3-(2-(arylethynyl)phenyl)prop-2-en-1-ols. A library of photocaged aryl aldehydes and ketones was synthesized, including those with donors and acceptors, fragrances, and the steroid 5α-cholestan-3-one, showing good to excellent photouncaging yields.
Article
Chemistry, Multidisciplinary
Beauty K. Chabuka, Igor V. Alabugin
Summary: To use holes as catalysts, the oxidation potential along the reaction path must increase, leading to hole upconversion. This study provides guidelines for the rational design of hole-catalyzed Diels-Alder reactions by evaluating the effects of substituents on the occurrence and magnitude of hole upconversion. Stereoelectronic effects can also activate or deactivate upconversion via a conformational change.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)