Palladium-Mediated Organofluorine Chemistry

Albéniz, Ana C.; Casares, Juan A.

doi:10.1016/b978-0-12-800976-5.00001-1

Cited by 23 publications

(20 citation statements)

References 380 publications

(228 reference statements)

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“…Compared to trifluoromethylation, C(sp 2 )−CF 2 bond‐forming reactions have been much less explored and new methods are therefore highly desirable. For this purpose, it is of interest to note that while there is still a lack of readily available, broadly useful electrophilic hypervalent(III) iodine CF 2 ‐transfer reagents, various functionalized halodifluoromethylated compounds [Hal−CF 2 −FG with FG=CO 2 Et, CONR 2 , PO(OEt) 2 , SO 2 Ph] have been recently shown to be convenient reagents to access difluoromethylated compounds by transition metal catalyzed (or mediated) coupling reactions, and notably those involving palladium . Only a limited number of palladium‐catalyzed difluoromethylation processes with functionalized difluoromethyl halides have been reported so far.…”

Section: Methodsmentioning

confidence: 99%

Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

et al. 2015

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A palladium-catalyzed C(sp(2))-H difluoromethylation of aldehyde-derived hydrazones using bromodifluoromethylated compounds to afford the corresponding functionalized difluoromethylketone hydrazones has been established. It is proposed that a radical/SET mechanism proceeding via a difluoroalkyl radical may be involved in the catalytic cycle. Applications of the methodology to the synthesis of α,α-difluoro-β-ketoesters and α,α-difluoroketones (RCOCF2 H) have been illustrated.

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Section: Methodsmentioning

confidence: 99%

Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

et al. 2015

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“…15 There are a few more personal reviews that treat C-H activation of fluoroarenes specifically 63,35 or address organofluorine chemistry at an individual metal. 64 We start this review with thermodynamic considerations, considering the energetics of free hydrofluorocarbons and then the energetics of C-H bond activation at a metal. We follow these general sections, with a survey of stoichiometric reactions divided up into reactions at atoms or ions and reactions in solution, dividing the latter into reactions with aliphatics, aromatics and alkenes.…”

Section: Scheme 1 Coordination Of Hydrofluoroarenes and Hydrofluoroamentioning

confidence: 99%

Selectivity of C–H Activation and Competition between C–H and C–F Bond Activation at Fluorocarbons

2017

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Partially fluorinated alkanes, arenes, and alkenes can be transformed by a variety of transition metal and lanthanide systems. Although the C-H bond is weaker than the C-F bond regardless of the hybridization of the carbon, the reaction of the C-F bond at the metal is usually more exothermic than the corresponding reaction of the C-H bonds. Both bonds are activated by the metal systems, but the preference for activating these bonds depends on the nature of the hydrocarbon and of the metal system, so that the reaction can be directed exclusively toward C-H or C-F bonds or yield a mixture of products. Additionally, the presence of fluorine differentiates between C-H bonds at different positions resulting in regioselective C-H bond activation; paradoxically, the strongest C-H bond reacts preferentially. The purpose of this review is to describe the field of reactions of partially fluorinated substrates with transition metal atoms, ions, and molecular complexes. The controlling physical properties (thermodynamics and kinetics) are described first, followed by a description of stoichiometric reactions, with the competition between the C-H and C-F activations as focus. A few representative catalytic systems are discussed. The review also highlights the benefit of combining experimental and theoretical studies.

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“…Fluorinated arenes are less reactive than their non-fluorinated analogues under standard Suzuki coupling conditions because of a difficult transmetalation step. 43 Since coupling preferably happens when the boronic acid group is meta to the fluoro substituent, 44 we attempted to use fluoroboroxarene monomer B3 as shown in Scheme 2. However, after modest success in the first coupling, further extension of the o-phenylene was unsuccessful.…”

Section: Design and Synthesismentioning

confidence: 99%

Fluorine Labeling of ortho-Phenylenes to Facilitate Conformational Analysis

et al. 2021

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1 H NMR spectroscopy is a powerful tool for the conformational analysis of orthophenylene foldamers in solution. However, as o-phenylenes are integrated into evermore-complex systems, we are reaching the limits of what can be analyzed by 1 Hand 13 C-based NMR techniques. Here, we explore fluorine labeling of o-phenylene oligomers for analysis by 19 F NMR spectroscopy. Two series of fluorinated oligomers have been synthesized. Optimization of monomers for Suzuki coupling enables an efficient stepwise oligomer synthesis. The oligomers all adopt well-folded geometries in solution, as determined by 1 H NMR spectroscopy and X-ray crystallography. 19 F NMR experiments complement these methods well. The resolved singlets of one-dimensional 19 F{ 1 H} spectra are very useful for determining relative conformer populations. The 1 additional information from two-dimensional 19 F NMR spectra is also clearly valuable when making 1 H assignments. Comparison of 19 F isotropic shielding predictions to experimental chemical shifts is not, however, currently sufficient by itself to establish o-phenylene geometries.

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Palladium-Mediated Organofluorine Chemistry

Cited by 23 publications

References 380 publications

Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

Selectivity of C–H Activation and Competition between C–H and C–F Bond Activation at Fluorocarbons

Fluorine Labeling of ortho-Phenylenes to Facilitate Conformational Analysis

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Palladium-Mediated Organofluorine Chemistry

Cited by 23 publications

References 380 publications

Palladium‐Catalyzed C(sp2)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

Palladium‐Catalyzed C(sp2)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

Selectivity of C–H Activation and Competition between C–H and C–F Bond Activation at Fluorocarbons

Fluorine Labeling of ortho-Phenylenes to Facilitate Conformational Analysis

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Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides

Palladium‐Catalyzed C(sp²)−H Alkylation of Aldehyde‐Derived Hydrazones with Functionalized Difluoromethyl Bromides