Selective C-H annulation with alkynes is one of the most useful tools to synthesize heterocycles. Herein, we developed novel porous organic polymers supported ruthenium (POPs-Ru) as highly efficient catalysts for cascade aromatization of quinoxalin-2(1)-one and C-H annulation with alkynes. Both terminal and internal alkynes were successfully transferred to furo[2,3]quinoxaline derivatives with good functional group tolerance and high regioselectivity by using POPs-Ru catalysts. Furthermore, the catalyst exhibited high activity and could be reused at least five times without obvious deactivation of this coupling reaction. This study offers an important platform for the immobilization of molecular metal catalysts for C-H functionalization.
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http://dx.doi.org/10.1021/acs.orglett.3c03056 | DOI Listing |
J Org Chem
January 2025
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210023, China.
We herein report a Rh(III)-catalyzed C-H bond coupling of -chloroimines with maleimides, in which the [4 + 2] annulation and dehydrogenative annulation processes can be selectively achieved by simply adjusting the reaction conditions. This protocol is compatible with various functional groups, shows exquisite selectivity, and presents a concise synthetic procedure to respective products in moderate to good yields. With all these merits, this strategy may be applicable in the construction of related azaheterocyclic skeletons.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, S. Kovalevskoy Street, 22, Ekaterinburg 620137, Russia.
The synthetic approach based on a sequence of Buchwald-Hartwig cross-coupling and annulation through intramolecular oxidative cyclodehydrogenation has been used for the construction of novel 4-alkyl-4-thieno[2',3':4,5]pyrrolo[2,3-]quinoxaline derivatives. For the first time, these polycyclic compounds were evaluated for antimycobacterial activity, including extensively drug-resistant strains. A reasonable bacteriostatic effect against HRv was demonstrated.
View Article and Find Full Text PDFMolecules
January 2025
Engineering Research Center of Tropical Medicine Innovation and Transformation of Ministry of Education, International Joint Research Center of Human-Machine Intelligent Collaborative for Tumor Precision Diagnosis and Treatment of Hainan Province, Hainan Provincial Key Laboratory of Research and Development on Tropical Herbs, School of Pharmaceutical Sciences, Hainan Medical University, Haikou 571199, China.
An efficient Rh(III)-catalyzed C-H activation of azobenzenes and subsequent [4+1] cascade annulation with CF-imidoyl sulfoxonium ylides was developed, yielding diverse CF-indazoles. This protocol featured easily available starting materials, excellent functional group tolerance and high efficiency. Moreover, the antitumor activities of selected CF-indazoles against human cancer cell lines were also studied, and the results indicated that several compounds displayed considerable antiproliferative activities.
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January 2025
School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, China.
Efficient access to pyranoisoquinoline derivatives via rhodium-catalyzed double C-H functionalization of phenyl oxadiazoles and diazo compounds has been developed. Two C-C bonds and one C-O and C-N bond formation was realized by this tandem reaction, along with the formation of two heterocycles, affording diversified pyran-fused isoquinolines in moderate to good yields with broad functional group tolerance under mild reaction conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States.
Monoanionic, bidentate-auxiliary-directed, cobalt-catalyzed C-H bond functionalization has become a very useful tool in organic synthesis. A comprehensive investigation into isolated organometallic intermediates and their reactivity within the catalytic cycle is lacking. We report here mechanistic studies of cobalt-catalyzed, aminoquinoline-directed C(sp)-H bond functionalization.
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