Article
Chemistry, Organic
Surya Pratap Singh, Shivani Arora, Prashant Kumar Bhardwaj, Anand Singh
Summary: An efficient and selective method for the synthesis of a spiro-chroman motif from quinone methides and 2-benzylidene dithiolanes catalyzed by PTSA is reported. The annulation reaction afforded spiro-chroman dithiolanes in high yields. The synthetic versatility of the dithiolane motif was demonstrated by converting the adduct to coumarin, 3,4-dihydrocoumarin, and chroman derivatives.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Yan Jiang, Hao-Jie Ma, Xue-Long Wang, Yi Yang
Summary: A Yb(OTf)(3)-catalyzed formal (4 + 3) cycloaddition reaction was successfully achieved using donor-acceptor cyclopropanes and 3-benzylideneindoline-2-thiones as reactants. Functionalized 5,10-dihydro-2H-thiepino[2,3-b]indole derivatives were synthesized with good yields and moderate to good diastereoselectivity. This reaction represents the first (4 + 3) cycloaddition of 3-benzylideneindoline-2-thiones.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Hongling Wang, Qiangqiang Zhang, Shuai Xiao, Guanjie Wang, Xuan Huang, Xingkuan Chen, Junmin Zhang
Summary: We have developed a N-heterocyclic carbene (NHC) and base-mediated [3 + 3] annulation reaction for the synthesis of enantioselective dihydropyrano[3,2-b]indoles. Easily prepared sulfonium salts were used as precursors and reacted with unsaturated acyl azolium to achieve this transformation. The reaction conditions are mild and result in privileged indole-fused dihydropyranones with moderate to good yields and excellent enantioselectivities.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Yan Jiang, Hao-Jie Ma, Xue-Long Wang, Yi Yang
Summary: A new compound was synthesized successfully in this study by using Yb-(OTf)(3) catalyst to react donor-acceptor cyclopropanes with sulfur-containing 4π components. The reaction showed high yields and moderate to good diastereoselectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Ruyu Xie, Zhiqiang Zhao, Yongxing Zhao, Rui Li, Jinzhong Yao, Maozhong Miao
Summary: Via Cu(I)-catalyzed cycloisomerization, readily available allenyl ketones bearing a cyclopropyl moiety can form in situ furan-fused cyclobutenes, which are highly reactive and powerful species that can undergo annulative fragmentation with terminal ynones to produce a wide variety of functional furans in moderate to high yields. This ring-distortion protocol features an unprecedented strain-controlled cycloisomerization/Diels-Alder/retro-Diels-Alder (CDRD) sequence under mild conditions.
Article
Chemistry, Organic
Jian-Xiang Zhu, Fu Pi, Teng Sun, Wen-Yu Huang, Lu Gao, Zhi-Chao Chen, Wei Du, Ying-Chun Chen
Summary: This article introduces a palladium-catalyzed tandem reaction that proceeds through sequential 2,4-dienylation/Michael addition/pi-sigma-pi isomerization/allylic alkylation. Using ortho-functionalized aryl enones and 2,4-dienyl carbonates as substrates, enantioenriched architectures with fused and spirocyclic frameworks are constructed in moderate to excellent yields and stereoselectivity. Importantly, the intrinsic intramolecular Diels-Alder reaction pattern of the dienylated intermediates is effectively reversed via Pd(0)-pi-Lewis base catalysis.
Article
Chemistry, Organic
Tao Wang, Wen-Bin Wang, Yan-Ming Fu, Cheng-Feng Zhu, Lan-Jun Cheng, Yang-En You, Xiang Wu, You-Gui Li
Summary: An asymmetric double oxidative [3 + 2] cycloaddition is reported, which generates highly functionalized chiral CF3-containing spiro[pyrrolidin-3,2'-oxindole] with four contiguous stereocenters stereoselectively. This method directly constructs two C-C bonds from four C(sp3)-H bonds, and it features mild conditions, broad substrate scope, and excellent functional group compatibility.
Article
Chemistry, Multidisciplinary
Zhimei Mao, Aimin Huang, Lin Ma, Min Zhang
Summary: A facile visible light-promoted approach has been developed for the synthesis of anthracenone-furans from readily available 2,3-dibromonaphthoquinones and phenylbenzofurans via a formal Diels Alder reaction. This reaction involves wavelength-selective agitation of 4CzIPN, energy transfer to quinones, recombination of 1,6-biradicals, and elimination to give anthracenone-furans in good to excellent yields in one pot.
Article
Biochemistry & Molecular Biology
Ekaterina A. Lystsova, Alexander S. Novikov, Maksim V. Dmitriev, Andrey N. Maslivets, Ekaterina E. Khramtsova
Summary: Acyl(imidoyl)ketenes can be used to synthesize diverse drug-like heterocycles. By utilizing the [4+2]-cyclodimerization of acyl(1,3-benzothiazol-2-yl)ketenes, a new synthetic approach to pharmaceutically interesting pyrido[2,1-b][1,3]benzothiazol-1-ones has been developed. Thermal analysis and computational studies revealed the suitability of 3-aroylpyrrolo[2,1-c][1,4]benzothiazine-1,2,4-triones as a source of acyl(1,3-benzothiazol-2-yl)ketenes, and a novel mode of thermal transformation of [e]-fused 1H-pyrrole-2,3-diones was discovered. The synthesized pyrido[2,1-b][1,3]benzothiazol-1-ones are of interest due to their potential antiviral activity.
Article
Chemistry, Organic
Brian J. J. Levandowski, Nile S. S. Abularrage, Ronald T. T. Raines
Summary: The reactivity of 5-membered dienes in Diels-Alder reactions can be adjusted through spirocyclization at the saturated center. Smaller spirocycles result in higher reactivity, with cyclobutane spirocycle, spiro[3.4]octa-5,7-diene, being the most reactive. Density functional theory calculations show that spiro[3.4]octa-5,7-diene dimerizes 220,000 times faster than 5,5-dimethylcyclopentadiene and undergoes a Diels-Alder reaction with ethylene 1200 times faster than 5,5-dimethylcyclopentadiene. These findings demonstrate the effectiveness of spirocyclization in enhancing the Diels-Alder reactivity of geminally substituted 5-membered dienes.
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Vikas Ashokrao Sadaphal, Rai-Shung Liu
Summary: Two different reaction chemoselectivities were observed for the reactions of alpha-aryldiazo ketone with 1,3-diphenylcyclopentadiene using gold catalyst and phosphine additives. The gold catalyst mainly facilitated C-H insertion reactions, while the phosphine additives enabled a new cycloaddition reaction for alpha-aryldiazo ketone.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
David M. Malouf, Abigail D. Richardson, Scott J. L'Heureux, Elizabeth A. McDonough, Ava M. Henry, Jerry Y. Sheng, Erica A. Medhurst, Angel E. Canales, Cameron J. Fleischer, Ty B. Cecil, Spencer E. Thurman, Cameron C. McMullen, Philip J. Costanzo, Daniel A. Bercovici
Summary: In this study, Ylidenenorbornadienes (YNDs) were prepared by [4 + 2] cyclo-additions and were found to react with beta-mercaptoethanol to yield a mixture of four diastereomers. These diastereomers exhibited retro-[4 + 2] cycloaddition at different rates. The rate constants of the diastereomers were extrapolated using a simulated kinetics approach. The fragmentation of YNDs showed a wide variability in rate, depending on the stereoelectronics of the ylidene substituents. Notably, a substrate containing one carboxylic ester exhibited exceptional stability to fragmentation.
Article
Chemistry, Multidisciplinary
Mikhail Feofanov, Dmitry Sharapa, Vladimir Akhmetov
Summary: This study reveals the alumina-mediated propargylic C-H activation, which converts common alkynes into valuable compounds under mild conditions. The partial hydroxylation of alumina's surface is demonstrated to play a crucial role in this reaction through theoretical investigation and experimental observations.
Article
Chemistry, Organic
Si-Si Ning, Dan Meng, Jie-Yun Zhang, Shi-Lei Liu, Ni-Ni Zhou, Xiaojie Jin, Hai-Tao Zhu
Summary: A metal-free intramolecular [3+2] cycloaddtion of benzene-linked propynol-ynes in AcOH/H2O has provided a greener and more practical route to functionalized naphtho[1,2-c]furan-5-ones with high regioselectivity. Additionally, regioselective alpha-deuteration of the naphtho[1,2-c]furan-5-ones showed excellent deuterium incorporation and yields. The fluorescent properties of the naphtho[1,2-c]furan-5-one products were also investigated in solution.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Gangming Xu, Suiqun Yang
Summary: Natural [4 + 2]-cyclases play a crucial role in the biosynthesis of natural products, with microbial [4 + 2]-cyclases exhibiting structural diversity and a broad substrate range. The evolutionary history and catalytic mechanisms of these cyclases, with 52 characterized so far, remain unclear.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Chemistry, Organic
Meng-Qiao Huang, Tuan-Jie Li, Jian-Quan Liu, Andrey Shatskiy, Markus D. Karkas, Xiang-Shan Wang
Article
Chemistry, Multidisciplinary
Xinyi Chen, Andrey Shatskiy, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: An unprecedented copper-catalyzed heteroaromatization/sulfonyl transfer of propargylic alcohols with isocyanide has been developed, resulting in the production of 3-sulfonyl benzofurans and indoles under Cu(I) catalysis in good to high yields. The developed catalytic methodology provides controlled, modular, and facile access to sulfonyl benzoheterocycle scaffolds.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Physical
Wenqian Fu, Chengyou Yin, Yu Feng, Lei Zhang, Feng Cheng, Zhongxue Fang, Chaojie Zhu, Tiandi Tang
Summary: The Cu/Beta-M catalyst exhibits superior catalytic performance in the difunctionalization of styrenes, attributed to the synergistic effect of Bronsted acid, copper species, and mesoporosity. Substrates with high electron density show increased reactivity towards the Cu/Beta-M catalyst.
APPLIED CATALYSIS A-GENERAL
(2021)
Article
Chemistry, Organic
Lanlan Lv, Yan Chen, Andrey Shatskiy, Jian-Quan Liu, Xiaoyi Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: A silver-catalyzed protocol for [3+1+1] annulation of nitrones and isocyanoacetates is reported, allowing access to a broad scope of valuable polysubstituted imidazoles in high yields through sequential [3+2] cycloaddition, ring-opening, cyclization-oxidation, and dealkylation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Editorial Material
Chemistry, Physical
Andrey Shatskiy, Jian-Quan Liu, Markus D. Karkas
Article
Chemistry, Organic
Yan Chen, Andrey Shatskiy, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: An unprecedented silver-promoted regioselective (4 + 1) annulation of isocyanoacetates with pyridinium salts is reported in this study, providing access to various synthetically useful N-fused heterocyclic scaffolds. The mechanism involves nucleophilic addition/protonation/elimination/cydoisomerization pathways. The protocol established in this research is controlled, facile, and modular.
Article
Chemistry, Organic
Li Xu, Xiaoyi Liu, Gregory R. Alvey, Andrey Shatskiy, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: The study presents a protocol for silver-catalyzed controlled intermolecular cross-coupling of silyl enolates, enabling the efficient preparation of a range of synthetically useful 1,4-diketones with good functional group tolerance. Preliminary mechanistic investigations indicate that the reaction proceeds through a one-electron process involving free radical species, with PhBr acting as the oxidant.
Article
Chemistry, Organic
Xin Geng, Andrey Shatskiy, Gregory R. Alvey, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: This study presents a protocol for a tandem Pd/Cu-catalyzed intermolecular cross-coupling cascade, providing a conceptually novel and controlled approach to synthesize N-fused (benzo)imidazophenanthridine scaffolds with high efficiency, broad substrate scope, and excellent functional group compatibility.
Article
Chemistry, Organic
Xin Geng, Heng He, Andrey Shatskiy, Elena V. Stepanova, Gregory R. Alvey, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: This study presents a straightforward synthetic approach for constructing phenanthridin-6(5H)-one skeletons. The method utilizes palladium catalysis and provides controlled access to various functionalized phenanthridin-6(5H)-ones in yields ranging from 59% to 88%. Plausible reaction pathways are proposed based on mechanistic experiments.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Weidong Jiang, Ye Li, Jian-Quan Liu, Xiang-Shan Wang
Summary: A protocol for a copper-catalyzed intermolecular cross-coupling cascade between 2-(2-bromoaryl)-1H-benzo[d]imidazole analogues and proline or pipecolic acid has been developed. The developed protocol allows efficient synthesis of a variety of N-fused pyrrolo or pyrido[1,2-a]imidazo[1,2-c]quinazoline scaffolds with good functional group compatibility. Proline or pipecolic acid acts as both ligand and reactant in the reaction, and a mechanistically consecutive approach for the Ullmann coupling, decarboxylation, oxidation, and dehydration reaction process was presented.
Article
Chemistry, Organic
Xin Geng, Heng He, Andrey Shatskiy, Elena V. Stepanova, Gregory R. Alvey, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: A straightforward synthetic approach for the construction of phenanthridin-6-(5H)-one skeletons is reported. Palladium catalysis is used to provide controlled access to a range of functionalized phenanthridin-6-(5H)-ones in yields of 59-88%. Plausible reaction pathways are proposed based on mechanistic experiments.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Heng He, Jian-Quan Liu, Xiang-Shan Wang
Summary: This study presents a copper-catalyzed sequence involving a Sonogashira coupling reaction and 5-exo-dig aminocyclization between a terminal alkyne and a 2-(2-bromophenyl)pyrimidine analog based on six-membered rings. The method provides a controlled and modular approach to access a variety of synthetically useful pyrimidine-fused skeletons with high efficiency, broad substrate scope, and excellent functional group compatibility. Under acidic conditions, the products undergo a spontaneous conversion of configuration to a specific structure.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Yi-Chun Wang, Xinyi Chen, Gregory R. Alvey, Andrey Shatskiy, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: Through a copper-assisted Wittig-type reaction, aldehydes are successfully transformed into (E)-vinyl sulfones by reaction with TosMIC. This method offers mild reaction conditions, simple operation, and compatibility with various common functional groups.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Hao Wu, Yi-Chun Wang, Andrey Shatskiy, Qiu-Yan Li, Jian-Quan Liu, Markus D. Karkas, Xiang-Shan Wang
Summary: A method using silver-catalyzed aerobic oxidation/6-endo heterocyclization of ortho-alkynylbenzaldehydes to produce 3-substituted isocoumarins has been developed. The protocol allows convenient access to a variety of useful compounds in good to high yields. Mechanistic studies suggest a free-radical pathway is involved.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Andrey Shatskiy, Anton Axelsson, Elena V. Stepanova, Jian-Quan Liu, Azamat Z. Temerdashev, Bhushan P. Kore, Bjorn Blomkvist, James M. Gardner, Peter Diner, Markus D. Karkas
Summary: A protocol for stereoselective C-radical addition to a chiral glyoxylate-derived N-sulfinyl imine was developed through visible light-promoted photoredox catalysis, providing a convenient method for the synthesis of unnatural alpha-amino acids. The protocol allows the use of ubiquitous carboxylic acids as radical precursors without prior derivatization. Alternative mechanisms for the developed transformation are discussed and corroborated by experimental and computational studies.
