Selective C4−F bond cleavage/C−O bond formation of polyfluoroarenes with phenols and benzyl alcohols

Liu, Cuibo; Cao, Liming; Yin, Xuguang; Xu, Haolan; Zhang, Bin

doi:10.1016/j.jfluchem.2013.08.013

Cited by 23 publications

(6 citation statements)

References 90 publications

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“…A competition reaction between C 6 F 5 CF 3 and C 6 F 5 CH 3 resulted in conversions of 31% and 49%, respectively, while C 6 F 5 CF 3 and C 6 F 5 CH 3 show similar reactivities in S N Ar reactions. 27 Although on the basis of these reactivity trends a nucleophilic substitution mechanism cannot be definitively excluded, the observed results seem to be better compatible with the participation of electrophilic species.…”

Section: Heterogeneous Catalytic Defluorination In Watermentioning

confidence: 84%

Catalytic Defluorination of Perfluorinated Aromatics under Oxidative Conditions Using N-Bridged Diiron Phthalocyanine

et al. 2014

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Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)Fe(IV)(μ-N)Fe(IV)(F)(Pc(+•))], which was isolated and characterized by UV-vis, EPR, (19)F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.

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Section: Heterogeneous Catalytic Defluorination In Watermentioning

confidence: 84%

Catalytic Defluorination of Perfluorinated Aromatics under Oxidative Conditions Using N-Bridged Diiron Phthalocyanine

et al. 2014

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“…The S N Ar reaction of ferrocenol ( 1 ) with dinitro aryl fluorides and 4‐nitrofluorobenzene proceeded, as expected, to give the respective ferrocenyl ethers, whereas fluorobenzene and 1,3‐difluorobenzene proved to be unsuitable. This low reactivity of C 6 H 5 F and C 6 H 4 F 2 has also been observed towards alkyloxy nucleophiles . Due to the mechanism of the reaction, a low electron density at the benzene ring enhances the reactivity and thus aryl fluorides with 3–6 ( 2a – d ) fluoro substituents were investigated (Schemes , , and ) , …”

Section: Resultsmentioning

confidence: 83%

“…However, compounds bearing more than three FcO ether substituents were not obtained within this reaction protocol, probably because of the thermal instability of 1 or the strong O–Li interaction . Thus, 6b and 9 equiv.…”

Section: Resultsmentioning

confidence: 99%

Multi‐Ferrocenyl Aryl Ethers – Applying Nucleophilic Aromatic Substitution Reactions to Aryl Fluorides

Korb

Lang

2016

Eur J Inorg Chem

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“…The alcohols could be diversified benzyl alcohols or cyclic or long‐chain aliphatic alcohols. The key to the successful formation of the corresponding products was the ideal combination of base, solvent, and reaction temperature (Scheme ) . A meaningful application of this strategy is the flexible creation of polyfluoroarylated diethers, triethers, and heterocyclic compounds via the continuous di‐ and trisubstituted process of polyphenols (Scheme ).…”

Section: Recent Achievements In the Transition‐metal‐free Snar Of Polmentioning

confidence: 99%

Facile Access to Fluoroaromatic Molecules by Transition-Metal-Free C-F Bond Cleavage of Polyfluoroarenes: An Efficient, Green, and Sustainable Protocol

Liu

Zhang

2016

The Chemical Record

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The creation of new bonds via C-F bond cleavage of polyfluoroarenes has proven to be an important and powerful tool in synthetic chemistry. Using such a strategy, a myriad of valuable partially fluoroaromatic molecules and building blocks can be obtained. The transition-metal-free nucleophilic aromatic substitution (SN Ar) strategy has aroused the continuing interest of researchers due to its simple, mild, economical, and environmentally benign characteristics, which have been successfully applied to C-F bond functionalizations. In this account, we present a summary of the recent investigations of polyfluoroarenes involving SN Ar reactions and discuss some of our recent endeavors in the construction of partially fluoroaromatic molecules. Through this strategy, many new bonds including C-C, C-N, C-O, C-S, and C-H bonds can be created. Additionally, brief discussions on the transformation mechanisms are also provided. Finally, we discuss the existing limitations of the SN Ar reactions of polyfluoroarenes as well as our perspective on the future development of this chemistry.

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Selective C4−F bond cleavage/C−O bond formation of polyfluoroarenes with phenols and benzyl alcohols

Cited by 23 publications

References 90 publications

Catalytic Defluorination of Perfluorinated Aromatics under Oxidative Conditions Using N-Bridged Diiron Phthalocyanine

Catalytic Defluorination of Perfluorinated Aromatics under Oxidative Conditions Using N-Bridged Diiron Phthalocyanine

Multi‐Ferrocenyl Aryl Ethers – Applying Nucleophilic Aromatic Substitution Reactions to Aryl Fluorides

Facile Access to Fluoroaromatic Molecules by Transition-Metal-Free C-F Bond Cleavage of Polyfluoroarenes: An Efficient, Green, and Sustainable Protocol

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