α-Fluorocarbanions are key intermediates in nucleophilic fluoroalkylation reactions. Although frequently discussed, the origin of the fluorine effect on the reactivity of α-fluorinated CH acids has remained largely unexplored. We have now investigated the kinetics of a series of reactions of α-substituted carbanions with reference electrophiles to elucidate the effects of α-F, α-Cl, and α-OMe substituents on the nucleophilic reactivities of carbanions.
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http://dx.doi.org/10.1002/anie.201605616 | DOI Listing |
J Am Chem Soc
January 2025
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Defluorination reactions are increasingly vital due to the extensive use of organofluorine compounds with robust carbon-fluorine (C-F) bonds; particularly, the efficient defluorination of widespread and persistent per- and polyfluoroalkyl substances under mild conditions is crucial due to their accumulation in the environment and human body. Herein, we demonstrate that surface-modified silicate of pronounced proton affinity can confine active hydrogen (•H) onto nanoscale zerovalent iron (nZVI) by withdrawing electrons from nZVI to react with bound protons, generating confined active hydrogen (•H) for efficient defluorination under ambient conditions. The exposed silicon cation (Si) of silicate functions as a Lewis acid site to activate the C-F bond by forming Si.
View Article and Find Full Text PDFJ Mol Model
January 2025
Departamento de Investigación y Desarrollo, ConsultoresAcademicos SpA, Moneda 1137, 8340457, Santiago, Chile.
Context: This study meticulously examines the criteria for assigning electron rearrangements along the intrinsic reaction coordinate (IRC) leading to bond formation and breaking processes during the pyrolytic isomerization of cubane (CUB) to 1,3,5,7-cyclooctatetraene (COT) from both thermochemical and bonding perspectives. Notably, no cusp-type function was detected in the initial thermal conversion step of CUB to bicyclo[4.2.
View Article and Find Full Text PDFChem Res Toxicol
January 2025
SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, Novosibirsk 630090, Russia.
Biological polyamines, such as spermine, spermidine, and putrescine, are abundant intracellular compounds mostly bound to nucleic acids. Due to their nucleophilic nature, polyamines easily react with apurinic/apyrimidinic (AP) sites, DNA lesions that are constantly formed in DNA by spontaneous base loss and as intermediates of base excision repair. A covalent intermediate is formed, promoting DNA strand cleavage at the AP site, and is later hydrolyzed regenerating the polyamine.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
While -phenylenediamine antioxidants (PPDs) pose potential risks to aquatic ecosystems, their environmental persistence and transformation remain ambiguous due to the undefined nature of PPD C-N bond hydrolysis. Here, we investigated the hydrolysis patterns of PPDs by analyzing their hydrolysis half-lives, hydrolysis products around neutral pH (pH 6.0-7.
View Article and Find Full Text PDFSynthesis (Stuttg)
January 2024
Department of Chemistry, Purdue University, 720 Clinic Drive, West Lafayette, Indiana 47907, USA.
alkaloid complanadine A, isolated by Kobayashi et al. in 2000, is a complex and unsymmetrical dimer of lycodine. Biologically, it is a novel and promising lead compound for the development of new treatment for neurodegenerative disorders and persistent pain management.
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