A chiral Lewis base catalyzed enantioselective -allylic alkylation of 2-hydroxypyridines and MBH carbonates is documented, affording a convenient access to -alkylated 2-pyridones with up to 99% ee and 99% yield. Experimental and computational studies have revealed that the strong hydrogen bond interaction between the chiral Lewis base catalyst and 2-hydroxypyridines plays a crucial role in this reaction for the reactivity, chemoselectivity, and enantioselectivity.
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http://dx.doi.org/10.1021/acs.orglett.2c03207 | DOI Listing |
Org Lett
January 2025
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China.
The azahelicenes are structurally fascinating and practically useful chiral scaffolds, but their synthesis, especially in a catalytically asymmetric manner, is rather challenging. Herein, we report a CPA-catalyzed transfer hydrogenation process, which enables a rapid kinetic resolution of aza[6]helicenes. The established strategy provides facile access to enantioenriched aza[6]helicenes and tetrahydro[6]helicenes from easily available starting materials.
View Article and Find Full Text PDFChem Sci
January 2025
Hunan Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University Changsha 410083 P. R. China
The layer-stacking mode of a two-dimensional (2D) material plays a dominant role either in its topology or properties, but remains challenging to control. Herein, we developed alkali-metal ion-regulating synthetic control on the stacking structure of a vinylene-linked covalent triazine framework (termed spc-CTF) for improving hydrogen peroxide (HO) photoproduction. Upon the catalysis of EtONa in Knoevenagel polycondensation, a typical eclipsed stacking mode (spc-CTF-4@AA) was built, while a staggered one (spc-CTF-4@AB) was constructed using LiOH.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Texas A&M University, Department of Chemistry, Texas A&M University, 77842, College Station, UNITED STATES OF AMERICA.
Lewis acids play a central role in a large variety of chemical transformations. The reactivity of the strongest Lewis acids is typically studied in the context of affinity towards hard bases, such as fluoride or oxygenous species. Carbocations can be viewed as soft Lewis acids, possessing significant affinity for softer bases, such as hydride.
View Article and Find Full Text PDFInorg Chem
January 2025
Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024, China.
The bipyridyl tantalum complex (2,6-PrCHO)Ta(bipy) () is synthesized by the reaction of (2,6-PrCHO)TaCl () and 2,2'-bipyridine in the presence of excess potassium graphite (KC). Complex coordinates readily with pyridine and 4-(dimethylamino)pyridine (dmap) to form Lewis base adducts (2,6-PrCHO)Ta(bipy)(L) (L = py (), dmap ()), and it exhibits rich redox reactivity toward small molecules: (a) single electron transfer (SET) occurs upon exposure of to phenyl sulfide or selenide dimer, giving the open-shell, bipy-centered radical complexes (2,6-PrCHO)Ta(bipy)(PhE) (E = S (), Se ()). (b) Regioselective C-C σ-bond formation via radical coupling is observed in the SET reaction of and aldehydes, ketones, or imines to furnish insertion products -, namely, sterically more crowded benzophenone, acetophenone, 2,6-dichlorobenzaldehyde, and benzophenone imine couple with C6 or C6' of bipy in , respectively, whereas sterically less hindered benzaldehyde, cyclohexanone, and benzylideneaniline couple with C2 or C2' of bipy, respectively.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin, 300071, China.
Polymer electrolytes incorporated with fillers possess immense potential for constructing the fast and selective Li conduction. However, the inhomogeneous distribution of the fillers usually deteriorates the microdomain consistency of the electrolytes, resulting in uneven Li flux, and unstable electrode-electrolyte interfaces. Herein, we formulate a solution-process chemistry to in situ construct gel polymer electrolytes (GPEs) with well-dispersed metal-organic frameworks (MOFs), leading to a uniform microdomain structure.
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