Article
Chemistry, Applied
Jing Huang, Bo Jiang, Xiyuan Zhang, Yanfeng Gao, Xiufang Xu, Zhiwei Miao
Summary: A synthetic strategy for accessing functionalized azabicyclo[3.3.1]alkenones with three tertiary stereocenters has been developed. The method is scalable and the products can be transformed to various eight-membered-ring bridged heterocyclic molecules.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Raghuramaiah Mandadapu, Amol Satish Dehade, Shrikant Abhiman Shete, Mark Montgomery, Vikas Sikervar, Ravindra Sonawane
Summary: Two different Lewis acids were utilized to achieve regioselective [3+2] and [3+3] cycloaddition reactions of an azomethine imine with activated cyclopropanes, resulting in moderate yields of tetrahydropyrazolone derivatives and tricyclic tetrahydrofuran derivatives as well as high regioselectivity in forming hexahydropyridazinone derivatives.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Organic
Jose Cortes Vazquez, Jacqkis Davis, Vladimir N. Nesterov, Hong Wang, Weiwei Luo
Summary: A formal [3 + 3] cyclization reaction has been developed for the synthesis of 1,3,4-oxadiazinanes with generally high yields (up to 96%). The reaction, catalyzed by Sc(OTf)(3), has a broad substrate scope for both diaziridines and quinones. The synergistic activation of 1,3-dipolar diaziridines and dipolar quinones was found to be essential for enabling this reaction.
Article
Chemistry, Multidisciplinary
Chen Chen, Xing-Xing Yang, Zhi Zhao, Bo Han, Wei Du, Ying-Chun Chen
Summary: In this study, the normal 1,3-dipolar cycloaddition between the carbonates of 4-hydroxy-2-cyclopentenones and C,N-cyclic azomethine imines was switched to an inverse-electron-demand version under Pd(0) catalysis. This transformation was achieved by in situ generation of HOMO-raised eta(2)-Pd(0)-cyclopentadienone complexes. The researchers constructed a variety of fused heterocyclic architectures with high levels of diastereo and enantioselectivity. Furthermore, diastereodivergent synthesis was realized by tuning the bifunctional phosphine ligands. A similar reaction with in situ formed thiophene-1,1-dioxide was also compatible by using a chiral bisphosphine ligand, leading to the formation of fused cyclic sulfone frameworks with high stereoselectivity.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Wu-Lin Yang, Tian-Tian Liu, Tao Ni, Bin Zhu, Xiaoyan Luo, Wei-Ping Deng
Summary: An iridium-catalyzed trifluoroacetic acid-promoted asymmetric cascade allylation/Pictet-Spengler cyclization reaction of azomethine ylides with aromatic allylic alcohols is reported, providing a facile and scalable method for the construction of 1,3,4-trisubstituted tetrahydroisoquinolines containing two stereogenic centers in good yields with generally excellent diastereo- and enantioselectivities. Additionally, a series of aromatic heterocyclefused piperidines were also obtained with excellent enantiocontrol by this methodology.
Article
Chemistry, Organic
Junfeng Fu, Ingrid Rakielle Tsapy Takia, Peng Chen, Wei Liu, Chengjun Jiang, Weijun Yao, Xiaofei Zeng, Yongjiang Wang, Xiaoyu Han
Summary: The phosphine-mediated tandem [3 + 2] cyclization/intramolecular Wittig reaction of 3-aroylcoumarin with alkynone allows the synthesis of 2-chromanone-fused bicyclo[3.2.0]heptenones in moderate to high yields with remarkably high regio- and diastereoselectivities under mild reaction conditions, providing an extremely simple, economical, and straightforward synthetic method for constructing complex cyclic building blocks with potential biological applications.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Hyun Ji Jeon, Su Min Park, Yu Lim Lee, Sang-gi Lee
Summary: The palladium-catalyzed divergent asymmetric synthesis of chiral spiro-furanindoline derivatives is described. The zwitterionic alkoxy pi-allyl Pd(II) intermediate, generated catalytically from vinyl ethylene carbonate (VEC), could undergo ligand-controlled enantio-and diastereoselective dipolar [3 + 2] spiroannulation with indole-based azadienes to afford the optically active spiro-furanindolines embedding an all-carbon quaternary stereocenter in high yields (up to 99%) with good to excellent stereoselectivities (up to 99% ee and up to >94:6 dr).
Article
Chemistry, Applied
Qi Huang, Chuanjiang Xiong, Yungui Peng
Summary: A diastereoselective (3+3) cycloaddition of azomethine imines and in situ-generated azaoxyallyl cations from a-halohydroxamate promoted by a Bronsted base has been developed. A series of pyrazolo [1,2-a][1,2,4]triazin-6-ones were accessed with up to 95% yields and diastereoselectivities greater than 20:1. The asymmetric version of this reaction was explored and moderate enantioselectivity was achieved after screening a series of cinchonine-derived chiral catalysts.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Min Liu, Leijie Zhou, Wangyu Shi, Yimin Hu, Jianning Liao, Zeqing Duan, Wei Wang, Yongjun Wu, Bing Zheng, Hongchao Guo
Summary: The delta-sulfonamido-substituted enones were utilized as phosphine acceptors in the phosphine-catalyzed (4 + 2) annulation of 1,1-dicyanoalkenes. They acted as a four-membered synthon to react with 1,1-dicyanoalkenes under mild reaction conditions, producing piperidine derivatives in moderate to excellent yields with good to excellent diastereoselectivities.
Article
Chemistry, Organic
Heng Zhang, Lu-Yu Cai, Kuo Wang, Hong-Wu Zhao
Summary: The chemical structure of the products obtained in the three-component decarboxylative coupling reactions among alkylidene pyrazolones, allyl carbonates, and active methylene compounds was unambiguously confirmed by single crystal X-ray analysis.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Applied
Zhongtao Yang, Xiai Luo, Zhipeng Zhang, Xiaoling Luo, Jia Zheng, Hui Luo, Weiguang Yang
Summary: In this study, a silver-catalyzed [3+2] diastereoselective annulation of p-quinamines and ketenimine zwitterionic salts was successfully carried out, leading to the synthesis of new compounds with specific stereochemical configurations. The relative stereoselectivity of the reaction can be controlled by specific functional groups. This method is significant for expanding the application of ketenimine zwitterionic salts.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Wei Li, Hengyuan Li, Jie Qiu, Zhenhui Wang, Xiaofeng Li, Ying-Ming Pan, Cheng Hou, Huaifeng Li
Summary: In this study, an efficient method for synthesizing 2-pyrazolines with a CF3- and alkyne-substituted quaternary carbon center is reported. This methodology offers high functional group compatibility, easily accessible reagents, and broad substrate scope.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Hongling Xie, Zhenkun Yang, Luning Tang, Zhengyu Han, Jianwei Sun, Hai Huang
Summary: This article describes a new synthetic approach for the synthesis of 9-membered N,N,O-heterocycles using Pd-catalyzed [6+3] dipolar cycloaddition. The scope of this cycloaddition is demonstrated with 28 examples, highlighting the importance of using N-iminoisoquinolinium ylides as ternary synthons for medium-sized ring synthesis.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Javier Corpas, Alberto Ponce, Ian Maclean, Javier Adrio, Juan C. Carretero
Summary: Chemodivergent cycloadditions of azomethine ylides with diphenylcyclopropenone have been developed, involving either Cu-catalyzed [3+3] or Ag-catalyzed [3+2] processes. These reactions provide a highly efficient method for the preparation of aromatic substituted dihydropyridinones and dihydropyrrolones with excellent regio and diastereoselectivities.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Applied
Siyang Xing, Tingxuan Gao, Changkun Jin, Hongguo Dong, Xueying Shao, Kui Wang, Bolin Zhu
Summary: A Cp*RhCl2-catalyzed formal [3+3]-cycloaddition involving sequential ring opening of aziridines initiated by C-H activation and Michael addition has been developed for the construction of cis-1,4-disubstituted tetrahydro-gamma-carbolines. The advantages of this strategy include broad substrate scope, excellent cis-diastereoselectivities, highly functionalized products, and mild conditions.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Applied
Luka Ciber, Sebastijan Ricko, Jure Gregorc, Franc Pozgan, Jurij Svete, Helena Brodnik, Bogdan Stefane, Uros Groselj
Summary: This study demonstrates that Arylidene-Delta(2)-pyrrolin-4-ones can undergo organocatalyzed annulation with malononitrile to form dihydropyrano[3,2-b]pyrroles. The enantiomeric excess of the products can be increased by trituration. The enantioselectivity depends on the nature of the substrate and the conformation of the catalyst, which is solvent-controlled. The reaction mechanism involves a Michael addition reaction step followed by 6-exo-dig annulation, and the rate determining step is the former, consistent with the proposed model.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Applied
Nejc Petek, Bibi Erjavec, Dejan Slapsak, Aljaz Gaber, Uros Groselj, Franc Pozgan, Sebastijan Ricko, Bogdan Stefane, Marina Klemencic, Jurij Svete
Summary: A series of new fluorescent compounds were synthesized via copper-catalyzed reactions, exhibiting interesting and promising optical properties. Some of them were successfully used for protein labeling.
Article
Environmental Sciences
Sanja Frka, Martin Sala, Helena Brodnik, Bogdan Stefane, Ana Kroflic, Irena Grgic
Summary: This study investigated the concentrations of nitroaromatic compounds (NACs) in aerosol samples from the urban background environment in Ljubljana, Slovenia. The study found that the concentrations of NACs were higher in winter compared to summer, with wood burning being the main source. The NACs also contributed significantly to the light absorption of the aerosols.
Article
Chemistry, Organic
Nejc Petek, Helena Brodnik, Oliver Reiser, Bogdan Stefane
Summary: A Cu(I)-photoredox-catalyzed trifluoromethylchlorosulfonylation reaction of terminal alkynes under visible light conditions has been developed. The reaction yields trifluoromethyl-substituted vinylsulfonyl chlorides, which can subsequently be coupled to a second alkyne under photocatalytic conditions. The method shows high regio- and stereoselectivity and can be applied to aliphatic and aromatic alkynes with various functional groups, producing synthetically valuable intermediates.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Luka Ciber, Franc Pozgan, Helena Brodnik, Bogdan Stefane, Jurij Svete, Mario Waser, Uros Groselj
Summary: Ten novel bifunctional quaternary ammonium salt phase-transfer organocatalysts were synthesized and evaluated for their organocatalytic activity in electrophilic heterofunctionalizations and the Michael addition reaction. The reactions showed high conversion rates, but low enantioselectivities. The catalysts were fully characterized and the stereochemistry at the C-2 chiral center was determined.
Article
Chemistry, Multidisciplinary
Maya Chochkova, Almira Georgieva, Tsvetelina Ilieva, Madlena Andreeva, Georgi Pramatarov, Nejc Petek, Petranka Petrova, Martin Sticha, Yavor Mitrev, Jurij Svete
Summary: A series of cinnamic acid hybrids were synthesized and their antioxidant properties were evaluated. The hybrids containing a caffeoyl moiety and lipophilic adamantane core exhibited higher antioxidant activity, suggesting their potential benefits in pathological conditions associated with oxidative stress.
JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Organic
Misel Hozjan, Luka Ciber, Franc Pozgan, Jurij Svete, Bogdan Stefane, Uros Groselj
Summary: A study on the organocatalyzed synthesis of tert-butyl 2-amino-3-cyano-5-oxo-4-phenyl-5,7-dihydropyrano[2,3-c]pyrrole-6(4H)-carboxylate from Boc-tetramic acid and benzylidenemalononitrile was presented. Two bifunctional noncovalent organocatalysts were used, resulting in the racemic mixture of the product in both cases. The structure of the newly synthesized compound was confirmed by high resolution mass-spectrometry, H-1- and C-13-NMR, HSQC, and IR spectroscopy.
Article
Chemistry, Organic
Luka Ciber, Franc Pozgan, Jurij Svete, Bogdan Stefane, Uros Groselj
Summary: A three-step synthesis of 1-{(1S,2S,4R)-7,7-dimethyl-1-[(pyrrolidin-1-yl)methyl]bicyclo[2.2.1]heptan-2-yl}-1H-benzo[d]imidazole from camphor derived diamine was reported. The absolute configuration of the chiral center bearing the benzo[d]imidazole moiety was confirmed using NOESY. The newly synthesized compound was characterized by H-1 and C-13 NMR, 2D NMR, IR spectroscopy, and high-resolution mass spectrometry.
Article
Chemistry, Organic
Kris Antolinc, Helena Brodnik, Uros Groselj, Bogdan Stefane, Nejc Petek, Jurij Svete
Summary: Irradiation of mixtures of title diazonium salts and heteroarenes with green light (510 nm) in the presence of eosin Y disodium salt (EY-Na-2) as a photocatalyst furnishes the corresponding arylation products in 8-63% yields. This method has a broad substrate scope and serves as a metal-free alternative for the synthesis of 3-heteroaryl-substituted 4Hquinolizin-4-ones and azino-and azolo-fused pyrimidones with a bridgehead nitrogen atom.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Luka Ciber, Helena Brodnik, Franc Pozgan, Jurij Svete, Bogdan Stefane, Uros Groselj
Summary: In this study, a monosubstituted benzene-1,2-diamine building block was prepared in two steps from commercially available compounds, and two new compounds were successfully synthesized.