Copper catalyzed azide-alkyne cycloaddition reaction (CuAAC) of non-fluorescent coumarin azides and sugar terminal alkynes afforded intense fluorescent 1,2,3-triazoles in 75-85% of yield. The photophysical properties of coumarin-sugar triazoles influenced greatly, upon introducing different substituents at 6th and 7th positions. The experimental observations were further supported by TD-DFT computational studies.
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http://dx.doi.org/10.1016/j.carres.2011.07.024 | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Here, we report the enantioselective total syntheses of four diepoxy--kaurane diterpenoids including (-)-Macrocalin B, (-)-Acetyl-macrocalin B, and (-)-Isoadenolin A and the revised structure of (-)-Phyllostacin I, which hinges on the strategic design of a regioselective and stereospecific trapping of a highly reactive [3.2.1]-bridgehead enone intermediate via a tethered intramolecular Diels-Alder reaction.
View Article and Find Full Text PDFOrg Lett
December 2024
Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, Nanning Normal University, Nanning 530001, P. R. China.
A palladium-catalyzed [2π + 2σ] cycloaddition of vinyl bicyclo[1.1.0]butanes with methyleneindolinones has been developed.
View Article and Find Full Text PDFOrg Lett
December 2024
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, New Cornerstone Science Laboratory, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China.
Reported herein is the generation of -quinone methides (-QMs) via metal-free visible-light-induced oxidation of -alkylarenols, as well as their subsequent reaction with olefins to afford chromans in good to excellent yields (up to 91%). The key is the selective activation of the benzylic C(sp)-H bond of -alkylarenols via single electron transfer (SET) and the formation of -QMs via hydrogen atom transfer (HAT).
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, 30 Puzhu Rd S., Nanjing 211816, China.
An electrochemical reductive bimolecular cycloaddition of 2-arylideneindane-1,3-diones has been reported for the synthesis of spirocyclopentanole indane-1,3-diones bearing five contiguous stereocenters with vicinal tetrasubstituted stereocenters, especially involving a quaternary carbon center, in moderate to good yields and excellent diastereoselectivities. The present protocol features mild reaction conditions, no external chemical redox reagents, excellent atom economy, and gram-scale synthesis. In addition, a mechanistic investigation indicates that the reactions proceed through a radical pathway.
View Article and Find Full Text PDFChem Rec
December 2024
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, 247667, India.
The 1,2,3-triazole-based chemosensors, synthesized through Cu(I)-catalyzed azide-alkyne cycloaddition via 'click chemistry', offer a straightforward yet highly effective method for detecting metal cations and anions with remarkable accuracy, selectivity and sensitivity, making them invaluable across various fields such as chemistry, pharmacology, environmental science and biology. The selective recognition of these ions is crucial due to their significant roles in biological and physiological processes, where even slight concentration variations can have major consequences. The article reviews literature from 2017 to 2024, highlighting advancements in the synthesis of 1,2,3-triazole-based ligands and their application (along with sensing mechanism) for detection of various ions causing health and environmental hazards.
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