Defluorinative functionalization of readily accessible trifluoromethyl groups constitutes an economical route to partially fluorinated molecules. However, the controllable replacement of one or two fluorine atoms while maintaining high chemoselectivity remains a formidable challenge. Here we describe a general strategy for sequential carbon-fluorine (C-F) bond functionalizations of trifluoroacetamides and trifluoroacetates. The reaction begins with the activation of a carbonyl oxygen atom by a 4-dimethylaminopyridine-boryl radical, followed by a spin-center shift to trigger the C-F bond scission. A chemoselectivity-controllable two-stage process enables sequential generation of difluoro- and monofluoroalkyl radicals, which are selectively functionalized with different radical traps to afford diverse fluorinated products. The reaction mechanism and the origin of chemoselectivity were established by experimental and computational approaches.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1126/science.abg0781 | 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 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.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESP), Beijing, China; Key Laboratory for Emerging Organic Contaminants Control (BKLEOC), Beijing, China; Laboratory for Environmental Frontier Technologies (BLEFT), School of Environment, Tsinghua University, Beijing 100084, China. Electronic address:
Widespread detection in soils and sediments underscores the potential threats posed by persistent, bioaccumulative and toxic perfluorooctane sulfonate (PFOS) to ecosystems and organisms. Nevertheless, the formidable energy of the C-F bond imparts stability and hampers degradation. This study investigates the potential of boron carbide (BC), a hard-ceramic material often utilized in armor and abrasion contexts, for degrading solid-phase PFOS through ball milling.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, Southern University of Science and Technology, Shenzhen 518055, PR China. Electronic address:
The persistence and ecological impact of per- and poly-fluoroalkyl substances (PFAS) in water sources necessitate effective and energy-efficient treatment solutions. This study introduces a novel approach using cerium dioxide (CeO) electrodes enhanced with oxygen vacancy (O) to catalyze the defluorination of PFAS. By leveraging the unique affinity between cerium and fluorine-containing species, our approach enables adsorptive preconcentration and catalytic degradation at low oxidation potentials (1.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!