A method for the catalytic, enantioselective, intramolecular 1,2-sulfenoamidation of alkenes is described. Lewis base activation of a suitable sulfur electrophile generates an enantioenriched, thiiranium ion intermediate from a β,γ-unsaturated sulfonyl carboxamide. This intermediate is subsequently intercepted by the sulfonamide nitrogen resulting in cyclization to form γ-lactams. Electron-poor alkenes required the use of a new selenophosphoramidate Lewis base catalyst. Subsequent manipulations of the products harness the latent reactivity of both the amide and thioether functionality.
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http://dx.doi.org/10.1021/acs.orglett.9b04347 | DOI Listing |
Angew 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.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States.
The viability of the P═Se bond to serve as a monitor of the strength of a noncovalent bond was tested in the context of the (CH)PSe molecule. Density functional theory (DFT) computations paired this base with a collection of Lewis acids that spanned hydrogen, halogen, chalcogen, pnicogen, and tetrel bonding interactions and covered a wide range of bond strengths. A very strong linear correlation was observed between the interaction energy and the nuclear magnetic resonance (NMR) J(PSe) coupling constant, which could serve as an accurate indicator of bond strength.
View Article and Find Full Text PDFMolecules
December 2024
Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 6, 95125 Catania, Italy.
The discriminative detection of volatile primary aliphatic diamines (VPADs) is a relevant and timely issue. This paper explores the distinctive optical features of H-type and J-type aggregates on paper-based (PB) films, namely H-PB and J-PB films, respectively, of a Lewis acidic Zn(salen)-type complex upon chemisorption of vapors of ditopic VPADs versus those of monotopic volatile amines. While volatile monotopic Lewis bases upon chemisorption give rise to mono-adducts accompanied by enhancement of the fluorescence, in contrast, VPADs act as ditopic bases forming di-adducts with distinct optical properties, leading to fluorescence quenching.
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