A directing-group-free palladium-catalyzed direct arylation of simple polyfluoroarenes with arylboronic acids through selective C-F bond activation is described. The combination of Pd(OAc) with BrettPhos was identified as an efficient catalytic system to promote the reaction with high regioselectivity and broad substrate scope. Preliminary mechanistic studies reveal that the oxidative addition of Pd to the C-F bond is involved in the catalytic cycle.
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http://dx.doi.org/10.1021/acs.orglett.8b00692 | DOI Listing |
Polarity reversal, or "umpolung", is a widely acknowledged strategy to allow organic functional groups amenable to react in alternative ways to the usual preference set by their electronic features. In this article, we demonstrate that cyclohexyne umpolung, realized through complexation to zirconocene, makes the small strained cycloalkyne amenable to C-F bond functionalisation. Such strong bond activation chemistry is unprecedented in "free" aryne and strained alkyne chemistry.
View Article and Find Full Text PDFBeilstein J Org Chem
January 2025
Sagami Chemical Research Institute, 2743-1 Hayakawa, Ayase, Kanagawa 252-1193, Japan.
2-Fluorobenzofurans underwent efficient nickel-catalyzed coupling with arylboronic acids through the activation of aromatic C-F bonds. This method allowed us to successfully synthesize a range of 2-arylbenzofurans with various substituents. The reaction, which proceeded under mild conditions, involved β-fluorine elimination from nickelacyclopropanes formed by the interaction of 2-fluorobenzofurans with zero-valent nickel species.
View Article and Find Full Text PDFJ 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 PDFChem Sci
January 2025
Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso, Showa-ku Nagoya 466-8555 Japan
In this study, we explore the potential of the difluoro(trifluoromethoxy)methyl group, CF-O-CF, an underexplored but promising structural analog of the trifluoromethoxy group (OCF). This moiety offers unique electronic properties and enhanced chemical stability due to its multiple C-F bonds, along with the added advantage of C-O bond cleavage, making it an attractive option in fluorine chemistry. We have succeeded in synthesizing difluoro(trifluoromethoxy)methyl compounds radical amino- and hydroxy-trifluoromethoxylations of β,β-difluorostyrenes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, Shandong University, Jinan 250100, P. R. China.
Herein, we describe a hexavalent tellurium-based chalcogen bonding catalysis platform capable of addressing reactivity and selectivity issues. This research demonstrates that hexavalent tellurium salts can serve as a class of highly active chalcogen bonding catalysts for the first time. The tellurium centers in these hexavalent catalysts have only one exposed interaction site, thus providing a favorable condition for the controlling of reaction selectivity.
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