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The mechanism of Pd(II)-catalyzed -C-H bond olefination of arenes with a carboxyl directing group (DG)-containing template has been investigated with density functional theory. The reaction includes three major steps: C-H bond activation, alkene insertion, and β-hydride elimination. The C-H activation step, which proceeds via a concerted metalation-deprotonation pathway, is found to be the rate- and regioselectivity-determining step. We proposed a mono-N-protected amino acid (MPAA)/DG-assisted C-H activation model, in which the carboxyl DG coordinates with the Pd center and delivers it to the -position of arene, and the bidentate dianionic MPAA acts as a base for deprotonation. There is a hydrogen bonding interaction between the carboxyl DG and the carboxylate group of MPAA. An alternative Pd(OAc)-catalyzed mechanism without involvement of MPAA is also operative. The template is conformationally flexible, and multiple low-energy transition-state conformations contribute to the regioselectivity.
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http://dx.doi.org/10.1021/acs.joc.1c01556 | DOI Listing |
Environ Pollut
September 2025
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Key Laboratory of Groundwater Pollution Simulation and Control Ministry of Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beiji
Paddy soil represents a critical sink for microplastics (MPs), where frequent redox oscillations from wet-dry alternation can accelerate MPs aging, and alter dissolved organic matter (DOM) composition in paddy soil. However, this process remains poorly understood to date. Here, we systematically investigated the aging of three MPs and their structural effects on DOM in paddy soil during wet-dry alternation.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore, Bengaluru560012, India.
The microwave spectrum of the complex formed between 1-fluoronaphthalene and HO has been recorded using a chirped pulse Fourier transform microwave spectrometer within the frequency range of 2.0 to 8.0 GHz, with neon as the carrier gas.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
State Key Laboratory of Antiviral Drugs, Tianjian Laboratory of Advanced Biomedical Sciences, Pingyuan Laboratory, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
The C-H functionalization represents a universal and important method for constructing new C-C bonds by carrying out reactions directly on inert C-H bonds. The major challenges are to control the site-selectivity and chemoselectivity because most complex organic compounds have many similar C-H bonds or different functional groups, such as a C═C bond or O-H bond. Here, we develop a versatile copper cluster (CuNC) with high stability and dynamic catalytic sites.
View Article and Find Full Text PDFBeilstein J Org Chem
September 2025
Department of Chemistry, Institute of Chemical Technology, Mumbai-400019, India.
Herein, we report a highly efficient, environmentally benign protocol for the domino synthesis of 2,4-disubstituted and 4-substituted quinoline molecules. The developed strategy involves an earth-abundant Fe-catalyzed C(sp)-C(sp) bond cleavage of styrene, followed by the hydroamination of the cleaved synthons with arylamines and subsequent C-H annulation to yield two valuable quinoline derivatives. Key features of this protocol include the use of O as an ideal, green oxidant, operational simplicity and scalability, high atom- and step-economy, and cost-effectiveness, collectively enabling the single-step synthesis of two medicinally relevant N-heterocycles in excellent combined yields.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080-3021, United States.
The direct transformation of C-H bonds into C-C bonds via cross-dehydrogenative coupling (CDC) represents a powerful strategy in synthetic chemistry, enabling streamlined bond construction without the need for prefunctionalized substrates. While traditional CDC approaches rely on polar mechanisms and preactivation of one of the C-H partners, recent advances have introduced radical-based strategies that employ a hydrogen atom transfer (HAT) approach to access carbon-centered radicals from unactivated substrates. Herein, we report a nickel-catalyzed CDC reaction between aldehydes and alkenes for the synthesis of skipped enones, leveraging aryl radicals as intermolecular HAT agents.
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