98-08-8Relevant articles and documents
A NEW METHOD FOR THE TRIFLUOROMETHYLATION OF AROMATIC COMPOUNDS
Marhold, A.,Klauke, E.
, p. 516 (1980)
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Aryl-CF3 Coupling from Phosphinoferrocene-Ligated Palladium(II) Complexes
Ferguson, Devin M.,Bour, James R.,Canty, Allan J.,Kampf, Jeff W.,Sanford, Melanie S.
, p. 519 - 526 (2019)
This article describes a detailed investigation of ligand effects on Ph-CF3 coupling from phosphinoferrocene-ligated PdII(Ph)(CF3) complexes. This study reveals that increasing the size of the phosphine substituents results in an enhanced rate of Ph-CF3 coupling, with (DtBPF)Pd(Ph)(CF3) (DtBPF = 1,1′-bis(di-tert-butylphosphino)ferrocene) being the most reactive complex. The mechanism of Ph-CF3 bond formation from both (DtBPF)Pd(Ph)(CF3) and (DiPrPF)Pd(Ph)(CF3) (DiPrPF = 1,1′-bis(diisopropylphosphino)ferrocene) was interrogated experimentally and computationally. These studies implicate a pathway involving concerted Ph-CF3 bond-forming reductive elimination from the four-coordinate PdII centers. An alternative pathway involving α-fluoride elimination and subsequent PhF2C-F coupling from PdII(CF2Ph)(F) intermediates was also evaluated but was ruled out based on DFT as well as the independent synthesis and reactivity studies of (DiPrPF)Pd(CF2Ph)(F).
Application of Visible-to-UV Photon Upconversion to Photoredox Catalysis: The Activation of Aryl Bromides
Majek, Michal,Faltermeier, Uwe,Dick, Bernhard,Pérez-Ruiz, Raúl,JacobivonWangelin, Axel
, p. 15496 - 15501 (2015)
The activation of aryl-Br bonds was achieved by sequential combination of a triplet-triplet annihilation process of the organic dyes, butane-2,3-dione and 2,5-diphenyloxazole, with a single-electron-transfer activation of aryl bromides. The photophysical and chemical steps were studied by time-resolved transient fluorescence and absorption spectroscopy with a pulsed laser, quenching experiments, and DFT calculations.
Mechanistic studies into visible light-driven carboxylation of aryl halides/triflates by the combined use of palladium and photoredox catalysts
Caner, Joaquim,Iwasawa, Nobuharu,Martin, Ruben,Murata, Kei,Shimomaki, Katsuya,Toriumi, Naoyuki
supporting information, p. 1846 - 1853 (2021/08/13)
The reaction mechanism of palladium-catalyzed visible light-driven carboxylation of aryl halides and triflates with a photoredox catalyst was examined in detail. Experimental and theoretical studies indicated that the active species for photoredox- catalyzed reduction was cationic ArPd(II)+ species to generate nucleophilic ArPd(I) or its further reduced ArPd(0)- species, which reacted with CO2 to give carboxylic acids. Hydrodehalogenated compounds, main byproducts in this carboxylation, were thought to be generated by protonation of these reduced species.
Photoredox-catalyzed reduction of halogenated arenes in water by amphiphilic polymeric nanoparticles
Eisenreich, Fabian,Kuster, Tom H. R.,Palmans, Anja R. A.,van Krimpen, David
supporting information, (2021/10/05)
The use of organic photoredox catalysts provides new ways to perform metal-free reactions controlled by light. While these reactions are usually performed in organic media, the application of these catalysts at ambient temperatures in aqueous media is of considerable interest. We here compare the activity of two established organic photoredox catalysts, one based on 10-phenylphenothiazine (PTH) and one based on an acridinium dye (ACR), in the light-activated dehalogenation of aromatic halides in pure water. Both PTH and ACR were covalently attached to amphiphilic polymers that are designed to form polymeric nanoparticles with hydrodynamic diameter DH ranging between 5 and 11 nm in aqueous solution. Due to the hydrophobic side groups that furnish the interior of these nanoparticles after hydrophobic collapse, water-insoluble reagents can gather within the nanoparticles at high local catalyst and substrate concentrations. We evaluated six different amphiphilic polymeric nanoparticles to assess the effect of polymer length, catalyst loading and nature of the catalyst (PTH or ACR) in the dechlorination of a range of aromatic chlorides. In addition, we investigate the selectivity of both catalysts for reducing different types of aryl-halogen bonds present in one molecule, as well as the activity of the catalysts for C-C cross-coupling reactions. We find that all polymer-based catalysts show high activity for the reduction of electron-poor aromatic compounds. For electron-rich compounds, the ACR-based catalyst is more effective than PTH. In the selective dehalogenation reactions, the order of bond stability is C-Cl > C-Br > C-I irrespective of the catalyst applied. All in all, both water-compatible systems show good activity in water, with ACR-based catalysts being slightly more efficient for more resilient substrates.