The synthesis of cyclic and bicyclic ureas via a ruthenium-catalyzed cross-metathesis / aza-Michael reaction strategy between protected alkenyl ureas and Michael acceptors is described. The substrates for these reactions are generated in 1-3 steps from commercially available materials, and products are formed in moderate yield with up to >20:1 diastereoselectivity.
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http://dx.doi.org/10.1021/acs.joc.8b01492 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Institute of Materials Research and Engineering, Sensor and Flexible Electronics, 2 Fusionopolis Way, 138634, SINGAPORE.
Radical covalent organic frameworks (RCOFs) have demonstrated significant potential in redox catalysis and energy conversion applications. However, the synthesis of stable RCOFs with well-defined neutral carbon radical centers is challenging due to the inherent radical instability, limited synthetic methods and characterization difficulties. Building upon the understanding of stable carbon radicals and structural modulations for preparing crystalline COFs, herein we report the synthesis of a crystalline carbon-centered RCOF through a facile post-oxidation process.
View Article and Find Full Text PDFOrg Lett
January 2025
Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, College of Chemistry & Chemical Engineering, Anhui University, Hefei, Anhui 230601, China.
Boron compounds are widely employed in organic chemistry, pharmaceuticals, and materials science. Among them, borylated heterocycles serve as versatile synthons for the construction of new C-C or C-heteroatom bonds via coupling or radical processes. Such methods for direct C-H borylation reactions are of high synthetic value to reduce the number of synthetic steps and the amount of waste and to improve efficiency.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Transition-metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS), have emerged as a generation of nonprecious catalysts for the hydrogen evolution reaction (HER), largely due to their theoretical hydrogen adsorption energy close to that of platinum. However, efforts to activate the basal planes of TMDs have primarily centered around strategies such as introducing numerous atomic vacancies, creating vacancy-heteroatom complexes, or applying significant strain, especially for acidic media. These approaches, while potentially effective, present substantial challenges in practical large-scale deployment.
View Article and Find Full Text PDFInorg Chem
January 2025
Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic University, 7098 Liuxian Blvd, Nanshan District, Shenzhen 518055, P. R. China.
Metal-organic frameworks have received extensive development in the past three decades, which are generally constructed via the reaction between inorganic building units and commercially available or presynthesized organic linkers. However, the presynthesis of organic linkers is usually time-consuming and unsustainable due to multiple-step separation and purification. Therefore, methodology development of a new strategy is fundamentally important for the construction and further exploration of the applications of MOFs.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
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