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Introducing distinctive functional groups to expand the structural diversity and improve the intrinsic properties of parent molecules has been an essential pursuit in organic chemistry. By using perfluoroalkyl halide (PFAH) as a nontraditional, readily available, ideal 1,2-difluoroalkenyl coupling partner, a defluorinative cyclization reaction of enamides for the construction of fluoroalkenyl oxazoles is first developed. The selective and controllable two-fold cleavage of vicinal C(sp)─F bonds in PFAH not only enables the introduction of a specific 1,2-difluoroalkenyl moiety with ease but also results in the functionalization of two C(sp)─H bonds of enamides without the need for metal catalyst, photocatalyst, oxidant, or light. The method can be applied to the late-stage modification of complex molecules, synthesis of biological-relevant oxazole analoges, and scale-up synthesis, which all further highlight the real-world utility of this protocol. Mechanistic studies reveal that the reaction possibly proceeds through a radical perfluoroalkylation, consecutive C─F bond heterolytic cleavage, and cyclization process. In addition, the in situ formed perfluoroalkyl radical which may also serve as an essential hydrogen abstractor.
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http://dx.doi.org/10.1002/advs.202404738 | DOI Listing |
Org Lett
July 2025
National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, China.
This study successfully developed a novel controllable defluorinative cyclization strategy for β-CF-1,3-enynes, achieving the divergent synthesis of pyrrolo[2,3-]pyrimidines and fluorinated pyrimidines. The reaction between β-CF-1,3-enynes and amidine hydrochlorides at a 1:2 molar ratio triggered selective [3+3]/[4+1] defluorinative cyclization, which efficiently constructed the pyrrolo[2,3-]pyrimidine framework. Notably, this work first reported that the process achieved cleavage/annulation of triple C-F bonds in the CF group of β-CF-1,3-enynes in a single step.
View Article and Find Full Text PDFOrg Lett
July 2025
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, China.
Herein, we present a chemoselective strategy for the divergent synthesis of γ-trifluoromethyl alcohols and difluorohomoallyl alcohols via photoredox-catalyzed hydroxyalkylation of α-CF alkenes with primary/secondary alcohols. Both products can further undergo base-mediated intramolecular defluorinative cyclization to construct monofluorinated dihydrofurans in a one-pot process. Through controllable C-F bond cleavage, this approach enables streamlined synthesis of three types of fluorinated products from abundant and inexpensive raw materials under mild photoredox conditions.
View Article and Find Full Text PDFAcc Chem Res
May 2025
The Institute for Advanced Studies, Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, Wuhan University, 299 Bayi Road, Wuhan 430072, China.
ConspectusCarbenes, as highly reactive intermediates, have emerged as pivotal tools in organic synthesis, catalysis, and materials science due to their versatile reactivity and broad applicability. Among the diverse classes of carbenes, donor-acceptor carbenes (DACs) have attracted significant attention owing to their unique electronic properties and exceptional reaction selectivity. The distinctive reactivity of DACs arises from the synergistic electronic interplay between electron-withdrawing and electron-donating groups attached to the carbene center, enabling a wide array of transformations.
View Article and Find Full Text PDFAdv Sci (Weinh)
July 2025
Department of Chemistry, Columbia University, 3000 Broadway, New York, NY, 10027, USA.
The introduction of F-containing groups into organic molecules can significantly alter their physical and chemical properties. Particularly, gem-difluoroalkenes serve as versatile precursors for a broad variety of organofluorine compounds, commonly used in agrochemicals, pharmaceuticals, and materials science. Based on the kinetics of H• transfer to acrylamide (k = 2.
View Article and Find Full Text PDFOrg Lett
March 2025
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, China.
A three-component cascade cyclization of α-CF alkenes, electron-rich alkenes, and dimethyl esters or sulfonamides via a dual C-F bond cleavage process is described. This methodology provides a general and efficient strategy to access monofluorocyclohexenes and 6-fluoro-1,2,3,4-tetrahydropyridines by switching the bifunctional reagents (dimethyl esters or sulfonamides), which are valuable building blocks in synthetic chemistry and the pharmaceutical industries. The reaction mechanism and the synthetic applications of the products have been demonstrated.
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