Cycloaddition reactions are highly attractive for post-synthetic modification of metal-organic frameworks (MOFs). We report herein on cycloaddition reactions with PIZOF(R(1),R(2))s, which are porous interpenetrated Zr-based MOFs with Zr(6)O(4)(OH)(4)(CO(2))(12) as the nodes and the dicarboxylates (-)O(2)C[PE-P(R(1),R(2))-EP]CO(2)(-) (P: phenylene, E: ethynylene; R(1), R(2): side chains at the central phenylene unit) as the linkers. 1,3-Dipolar cycloaddition between the pendant ethyne moieties of PIZOF(OMe,OCH(2)C≡CH) and 4-methylbenzyl azide resulted in 98% conversion of the ethyne groups. Reactions of PIZOF(OMe,O(CH(2))(3)furan) with maleimide, N-methylmaleimide, and N-phenylmaleimide converted 98, 99, and 89% of the furan moieties into the Diels-Alder adducts. However, no reaction occurred with maleic anhydride. High-resolution (1)H NMR spectra were crucial in determining the conversion and identifying the reaction products. Of all the reagents (NaOD/D(2)O, D(2)SO(4), Bu(4)NF, CsF, CsF/DCl, and KHF(2)) tested for the disassembly of the PIZOFs in [D(6)]DMSO, the combination of CsF and DCl was found to be the best. The disassembly at room temperature was fast (5-15 min), and after the addition of K(2)CO(3) the (1)H NMR data were identical to those of the diacids (=protonated linkers) dissolved in pure DMSO. This allowed for simple structure elucidation through data comparison. CsF/DCl dissolves not only PIZOFs but also the hydrolytically very stable UiO-66.
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http://dx.doi.org/10.1002/chem.201103288 | DOI Listing |
J Org Chem
January 2025
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin 541004, China.
A cascade reaction of Pd(II)/dppben-catalyzed [3 + 2] cycloaddition of -aryl nitrones with allenoates and sequential reduction has been developed for the synthesis of functionalized benzazepines bearing three contiguous carbon stereocenters in moderate to good yields ranging from 15 to 82% and high diastereoselectivity. The obtained benzazepines could be converted into various benzazepine scaffolds, and an estrone-derived benzazepine scaffold was prepared over four steps from estrone. More importantly, chiral benzazepine bearing three contiguous carbon stereocenters could be obtained in 88% ee value with chiral auxiliary.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Key Laboratory of Green Chemical and Clean Energy Technology, School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, P. R. China.
Electron-induced effects, which are prevalent in adsorption and heterogeneous catalytic reactions, can significantly influence the state and uptake of adsorbates. Here, we demonstrate the in situ doping of electron-deficient boron into the backbone of chitosan-based porous carbon materials. Despite a reduction in specific surface area, the resulting boron-doped porous carbons (NBPCs) exhibit an enhanced CO adsorption performance, with sample NBPC-10 achieving CO adsorption capacities of 7.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Catalysis Laboratory, School of Chemistry, University of Hyderabad, Hyderabad-500 046, India.
Benzothiazole and benzoxazole heterocyclic ring-containing 1,4,5-trisubstituted-1,2,3-triazoles are well known for their wide range of applications in pharmaceutical and medicinal chemistry, but their high-yielding metal-free selective synthesis has always remained challenging as no comprehensive simple protocol has been outlined to date. Owing to their structural and medicinal importance, herein, we synthesized various benzothiazole and benzoxazole heterocyclic ring-containing 1,4,5-trisubstituted-1,2,3-triazoles in high to excellent yields with chemo-/regioselectivity from the library of benzothiazole/benzoxazole-ketones and aryl/alkyl-azides through an enolate-mediated organocatalytic azide-ketone [3 + 2]-cycloaddition under ambient conditions in a few hours. The commercial availability or quick synthesis of the starting materials and catalysts, a diverse substrate scope, chemo-/regioselectivity, quick synthesis of pharmaceutically active known compounds and their analogues, and numerous medicinal applications of functionalized benzothiazole/benzoxazole-triazoles are the key attractions of this metal-free organo-click reaction.
View Article and Find Full Text PDFJ Org Chem
January 2025
Key Laboratory of Biomass Green Chemical Conversion of Yunnan Provincial Education Department, Yunnan Key La-boratory of Chiral Functional Substance Research and Application, School of Chemistry & Environment, Yunnan Minzu University, Kunming 650504, P. R. China.
We report a base-promoted, metal-free multicomponent tandem reaction, involving a [4 + 1 + 1] cycloaddition process between -substituted nitroarenes, aldehydes, and ammonium salts. Modifying the substituents on the nitroaromatic compounds effectively provides structurally diverse 2-substituted and 4-alkenylquinazolines with good to excellent yields (77%-90% and quinazoline 51 examples) and high tolerance for various inorganic ammonium salts (13 examples, such as NH·HO, NHCl, and NHHF). A new method for constructing 2,4-substituted quinazoline compounds with high selectivity from simple nitrogen source compounds was developed, and the reaction can be scaled up to a gram scale.
View Article and Find Full Text PDFNat Commun
January 2025
College of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, Changchun, P. R. China.
The enantioselective domino Heck/cross-coupling has emerged as a powerful tool in modern chemical synthesis for decades. Despite significant progress in relative rigid skeleton substrates, the implementation of asymmetric Heck/cross-coupling cascades of highly flexible haloalkene substrates remains a challenging and and long-standing goal. Here we report an efficient asymmetric domino Heck/Tsuji-Trost reaction of highly flexible vinylic halides with 1,3-dienes enabled by palladium catalysis.
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