Article
Chemistry, Inorganic & Nuclear
Felipe de la Cruz-Martinez, Marc Martinez de Sarasa Buchaca, Juan Fernandez-Baeza, Luis F. Sanchez-Barba, Ana M. Rodriguez, Jose A. Castro-Osma, Agustin Lara-Sanchez
Summary: Despite the widespread interest in zinc catalysis for hydroelementation reactions, the use of zinc complexes as catalysts for the hydroalkoxylation of alkynyl alcohols has not been reported. However, scorpionate zinc complexes have been successfully designed as precatalysts for this reaction. Studies have shown the excellent selectivity of zinc amide complex 8 in promoting the intramolecular hydroalkoxylation process to yield exocyclic enol ethers under mild conditions.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Hayeon Kwak, Eunsu Kang, Jae Yeong Song, Geunhee Kang, Jung Min Joo
Summary: The development of modular approaches for heteroaromatic cores and substituents is crucial for drug candidates and organic functional materials. A new strategy involving the cyclization of heteroarenes tethered with alkynes through a norbornene bridge was developed. The Pd catalytic system transformed a variety of five-membered heteroarenes to the corresponding benzofused products, demonstrating its versatility in the annulation of (hetero)aromatic rings.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Ketan Kumar, Prashant Kumar, Bara Singh, Sonu Yadav, Uttam K. Mishra, Arshad J. Ansari, S. S. Ramasastry
Summary: The catalysis by transition metals is a powerful tool to access molecules with broad structural and functional diversity. Recent literature has shown the tremendous potential of transition metal-catalyzed processes in advancing organic synthesis. New conceptual advancements in palladium-catalyzed Alder-ene type cycloisomerization reactions, C-H functionalizations, and one-pot multicatalytic processes have become essential tools to access new classes of molecules.
Article
Chemistry, Organic
Bo Li, Yunhao Zhou, Yue Xu, Xiang Li, Zheyu Li, Linghui Gu, Wenbo Ma, Ruhuai Mei
Summary: In this study, an unprecedented electrochemical reaction for regioselective selenation/cyclization of alkynyl phosphonates with diselenide was described. Valuable cyclic enol phosphonate or phosphaisocoumarins were obtained under electrochemical and transition-metal-free conditions. The compatibility of these transformations with complex natural products and bioactive molecules was demonstrated. The selenoether and halogen functional groups allow further diversification of the obtained phosphorus heterocycles.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ren-Xiao Liang, Ling-Jie Song, Jin-Bo Lu, Wei-Yan Xu, Chao Ding, Yi-Xia Jia
Summary: The study presents a PdH-catalyzed enantioselective heteroarenyne cycloisomerization reaction and a classical enantioselective 1,5-enyne cycloisomerization of N-vinylpropiolamides, showcasing the synthesis of diverse chiral spiro and fused indoline derivatives as well as chiral 2-pyrrolones with good to excellent enantioselectivities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Can Chen, Zhe Tian, Wanjie Liang, Jintao Guo, Ping Xiao, Zhenlei Wang, Lizhi Zhang, Qing Liu, Hui Liu
Summary: A ligand-free palladium-promoted [1,8]-sigmatropic hydrogen shift reaction of 1,6-allene-ene was reported, which involved an intramolecular Ene cyclization using base as a hydrogen shuttle. The transformation achieved hydrogen atom transfer (HAT) by shifting the allylic C-H bond to a new one with low bond dissociation energy (BDE) distinction. The mild reaction conditions, high atom economy, and good chemo/regioselectivity highlighted the significance of this strategy.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Logan E. Vine, Ryan D. Reeves, Eleanor M. Landwehr, Israel Fernandez, Jennifer M. Schomaker
Summary: This study demonstrates predictable control over the mechanism of Pd-catalyzed allene cross-coupling/cyclization and cycloisomerization by targeted changes to the reaction conditions, resulting in the successful access to enantioenriched cyclopropanes and cyclopentenes. Furthermore, it shows a simple switch of the ligand on Pd can divert the reactivity of allenyl malonate from cross-coupling/cyclization to cycloisomerization.
Article
Chemistry, Multidisciplinary
Jinghui Yang, Yan Xia
Summary: The researchers developed a novel polymer system that undergoes extensive backbone degradation in response to mechanical stress, synthesized through ring-opening metathesis polymerization and enhanced thermal stability through hydrogenation. The polymers can be easily degraded into small molecule or oligomeric species under mildly acidic conditions.
Article
Chemistry, Multidisciplinary
Franziska Spruner von Mertz, Ricardo Molenda, Sebastian Boldt, Alexander Villinger, Peter Ehlers, Peter Langer
Summary: A series of previously unknown 5,14-diphenylbenzo[j]naphtho[2,1,8-def][2,7]phenanthrolines, incorporating a 5-azatetracene and a 2-azapyrene subunit, were successfully synthesized using Pd-catalyzed cross-coupling reactions and a one-pot Povarov/cycloisomerization reaction. This synthetic approach enables extensive diversification of the heterocyclic core structure. The optical and electrochemical properties of these compounds were investigated through experimental and computational studies, revealing their closer electronic and optical resemblance to 2-azapyrenes rather than the typical characteristics of 5-azatetracene moieties.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Felipe Verdugo, Ricardo Rodino, Martin Calvelo, Jose Luis Mascarenas, Fernando Lopez
Summary: The reactivity of carbonyl-tethered alkylidenecyclopropanes (ACPs) can be directed towards tandem cycloisomerization/cross-coupling processes by using Pd-0 catalysts with phosphorus-based monodentate ligands. This allows for the synthesis of a wide variety of highly functionalized cyclic alcohols and amines through the formation of key pi-allyl oxapalladacyclic intermediates which are trapped with external nucleophilic partners.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Li Pang, Shu-Jun Fang, Pei-Sen Zou, Wang Wang, Jun-Cheng Su, Xiao-Qing Liu, Cheng-Xue Pan, Dong-Liang Mo, Gui-Fa Su
Summary: We report a transition-metal free [4 + 4] cycloaddition reaction between 2-alkynyl quinazolines and aza-ortho-quinone methides (ao-QMs) generated from 2-(bromomethyl)anilines, leading to the synthesis of various [1,5]diazocino[2,1-b]quinazolinones in good to excellent yields under mild reaction conditions and short reaction time. Furthermore, a [1,5]diazocino[2,1-b]quinazolinone derived from estrone was easily prepared in 30% total yield over five steps, and showed significant inhibition of nitric oxide generation in LPS-stimulated RAW264.7 cells. This method offers advantages such as broad substrate scope, gram-scale preparation, and simple purification operation without flash column chromatography.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Qi Li, Zi-Lu Wang, Huan-Xuan Lu, Yun-He Xu
Summary: A copper-catalyzed 1,4-protosilylation of alpha-alkynyl-enones has been developed to prepare functionalized chiral homoallenylsilanes with a contiguous stereogenic center and axis, showing good yields and excellent enantioselectivities and diastereoselectivities.
Article
Chemistry, Applied
Shulin Ge, Xiao-Ying Yang, Xiuting Lv, Guiyue Fang, Xia Xiao, Chengting Zi, Qiangqiang Zhu, Xuanjun Wang
Summary: This research reported a silver-catalyzed tandem cycloisomerization/Povarov reaction between beta-alkynyl ketones and hexahydro-1,3,5-triazines, providing access to spiro[isochromene-1,4'-quinoline]. This synthetic protocol demonstrated remarkable efficiency, low catalyst-loading, and high diastereoselectivity, enhancing the drug-like properties of planar bioactive molecules. Furthermore, the spirocyclic quinolines exhibited good cytotoxicity in U937 cells by exclusively activating the Notch-signaling pathway.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Paul Shaw, Storm J. Hassell-Hart, Gayle E. Douglas, Andrew G. Malcolm, Alan R. Kennedy, Gemma White, Laura C. Paterson, William J. Kerr
Summary: In this study, we applied silyl enol ether moieties as efficient alkene coupling partners within cobalt-mediated intramolecular Pauson-Khand reactions. This cyclization strategy delivers valuable oxygenated cyclopentenone products in high yields and allows for the incorporation of a variety of decorated structures.
Review
Chemistry, Organic
Soumilee Nandy, Swagata Paul, Kanak Kanti Das, Parveen Kumar, Debraj Ghorai, Santanu Panda
Summary: Organoboron chemistry has seen considerable advancements over the last century, with alkynyl boron compounds garnering significant attention for their easy synthesis and diverse reactivity. These compounds play an important role in the synthesis of valuable compounds.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Ganesh More, Pushpa Malekar, Rupali G. Kalshetti, Mahesh H. Shinde, Chepuri Ramana
Summary: This study demonstrates the Ru-catalyzed enantio- and diastereoselective dynamic kinetic resolution of alpha-(benzyloxy/benzoyloxy)acyl-gamma-butyrolactones via transfer hydrogenation. Excellent diastereo- and enantioselectivities were achieved with the in situ prepared (R,R)-Ru-FsDPEN catalyst, leading to the synthesis of important organic molecules with good efficiency.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Organic
Pawan S. Dhote, Chepuri Ramana
Summary: The [Au]-catalyzed nitroalkyne cycloisomerization process leading to anthranils may be affected by the trapping of the postulated intermediate alpha-oxo gold carbene with external nucleophiles. This study also provides evidence for the synthesis of highly functionalized indazoles through sequential bond formations.
Article
Chemistry, Organic
Sibadatta Senapati, Nivedya A. Unmesh, Manoj N. Shet, Iram Ahmad, Nandu Ajikumar, Chepuri V. Ramana
Summary: This paper describes a highly diastereoselective total synthesis of several bis-THF C-15 acetogenin natural products, as well as the synthesis of an advanced intermediate reported in the total synthesis of (E/Z)-elatenynes. Key features in the synthesis include epoxide opening, Birch reduction, Sharpless asymmetric dihydroxylation-cycloetherification, S(N)2 halogenation, and a relay cross metathesis.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Multidisciplinary
Pawan S. Dhote, Swapnil V. Halnor, Chepuri V. Ramana
Summary: The article discusses the gold-catalysed intramolecular redox cyclization of o-alkynylnitrobenzens, highlighting its importance and potential for further research in metal catalysis. It also touches upon the idea of generating alpha-oxo gold carbenes via oxygen transfer to alkynes, establishing another significant aspect in gold catalysis.
Article
Chemistry, Organic
Pawan S. Dhote, Kishor A. Pund, Chepuri Ramana
Summary: The known nitrogen-transfer reagent 1,2-benzo[d]isoxazole has been used to trap the postulated α-oxo gold carbene intermediate involved in the [Au]-catalyzed internal redox process of 2-alkynylnitrobenzenes. This process led to the development of a general convergent method for the synthesis of highly functionalized quinazoline 1-oxides.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Pawan S. Dhote, Chepuri Ramana
Summary: In this study, the possibility of interrupting the gold-catalysed intramolecular cyclization was explored in order to develop simple tools for product diversification. It was found that using 1,2-benzisoxazoles, intermolecular nitrene transfer competed with intramolecular azidoalkyne cyclization resulting in spiro indol-3-ylidene derivatives. However, when anthranil was present, both intra- and intermolecular nitrene transfer processes led to the same product indol-3-ylidene.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Pawan S. Dhote, Chepuri Ramana
Summary: The hydrazine/phenylhydrazine-mediated reductive dicarbonyl coupling reactions have been successfully carried out under mild conditions, providing polycyclic aromatic compounds and azo-substituted polyaromatic compounds with a broad substrate scope and good functional group compatibility.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Mahesh H. Shinde, Chepuri Ramana
Summary: A simple method for synthesizing pyridoindolone scaffolds with a spiroannulated tetrahydrofuran ring is described. The method involves intramolecular gold-catalyzed cycloisomerization and subsequent addition of indole C2 to the in situ generated oxocarbenium cation.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Rupali G. Kalshetti, Swapnil V. Halnor, Chepuri V. Ramana
Summary: The Rh-catalyzed cross dehydrogenative coupling (CDC)/alkylation reaction was successfully carried out under ambient conditions, selectively on the pyrazole unit while directed by the pyridine. The scope of these reactions was demonstrated by using simple and conjugated olefins for CDC and various diazo esters and the TIPS-EBX reagent for alkylation. A small molecule library based on the bis-heterocyclic core of GBT440 was developed via C-H functionalization.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Organic
Manoj N. Shet, Hemanth K. Nechooli, Chepuri V. Ramana
Summary: A simple method was developed for constructing the tetracyclic spiroketal skeleton of Lycibarbarine A and B. By coupling the fragments through epoxide opening with tetrahydroquinoline under solvent-free conditions, followed by oxidation and TBAF-mediated silyl deprotection spiroketalization, the complete tetracyclic core present in these natural products was established.
TETRAHEDRON LETTERS
(2023)
Article
Crystallography
Shaziyaparveen K. Siddiqui, C. V. Ramana, Rajesh G. Gonnade
Summary: The title compound crystallizes in monoclinic space group P2(1)/n with a planar geometry. The crystal structure is consolidated by C-H···O hydrogen bonding and a short C=O···CC (acetylene) contacts. Hirshfeld surface analysis indicates that H···H, C···H/H···C, and H···Br/Br···H interactions play a more important role in consolidating the crystal structure compared to H···O/O···H and C···C contacts.
ACTA CRYSTALLOGRAPHICA SECTION E-CRYSTALLOGRAPHIC COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Swapnil V. V. Halnor, Pawan S. S. Dhote, Chepuri V. V. Ramana
Summary: A new catalytic method has been developed to construct the quinobenzoxazine core by employing gold-catalyzed cyclization of o-azidoacetylenic ketones in the presence of anthranils. The process involves a 6-endo-dig cyclization of o-azidoacetylenic ketone catalyzed by gold, leading to the formation of an alpha-imino gold carbene, which then transfers to anthranil to form the 3-aryl-imino-quinoline-4-one intermediate. This intermediate undergoes 6 pi-electrocyclization and aromatization to form the central quinobenzoxazine core. This transformation provides a new and scalable approach to diverse quinobenzoxazine structures under mild reaction conditions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Mahesh H. Shinde, Chandrababu N. Kona, Chepuri Ramana
Summary: This study documents the gold catalysed alkynediol spiroketalization for assembling the central spiro-bis-THF fragments of symbiospirols A-C. The chiral pool approach using commercially available d-glucose and l-malic acid was employed to synthesize key building blocks. Additionally, two other possible diastereomers were synthesized to determine the relative stereochemistry of the unassigned THF-center of symbiospirols B/C.
NEW JOURNAL OF CHEMISTRY
(2022)
Review
Chemistry, Organic
Pawan S. Dhote, Pitambar Patel, Kumar Vanka, Chepuri V. Ramana
Summary: The pseudoindoxyl sub-structural motif is a unique subset of the oxygenated indole class of alkaloids, with interesting biological profiles. The challenges and future perspectives of synthesizing pseudoindoxyl compounds will be discussed based on recent developments.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Sibadatta Senapati, Chepuri Ramana
Summary: A simple approach for synthesizing the C14-C28 fragment of eribulin has been developed by utilizing one-pot gold-catalyzed alkynol cyclization/Kishi reduction and cross-metathesis/Sharpless asymmetric dihydroxylation-cycloetherification reactions. The use of easily accessible building blocks and catalytic transformations highlights the efficiency of the method in constructing the THF/THP units for eribulin synthesis.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Fuying Zhu, Yamei Lin
Summary: In this study, a low-metal iron-supported catalyst (Fe20/NC-Mg) was reported for the efficient synthesis of quinoxaline compounds, using water as a solvent and without additional bases. The synergistic effect of FeNx site and Mg (OH)2 nanorods in the catalyst played a key role in achieving high yields (82-91%) in 16 examples. The gram-level synthesis and reusability of the catalysts after four cycles demonstrated its industrial application potential.
Article
Chemistry, Organic
Mikhail Kozlov, Alexey Tyurin, Andrey Dmitrenok, Vyacheslav Rusak, Aleksander Fedorov, Igor Zavarzin, Yulia Volkova
Summary: This study presents a novel and practical synthesis method for phosphorus-substituted 1,3,4-thiadiazolines using phosphorylthioformic acid hydrazides and ketones. The protocol demonstrates operational simplicity, availability of reagents, and tolerance towards different functional groups.
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.
