Iron-catalyzed dimerization of various isatin derivatives is described for the efficient synthesis of 3,3'-biindolinylidene-diones (isoindigos). The reaction provides easy access to self-coupled and cross-coupled 3,3'-indolinylidene-diones that have high relevance to biology and materials. This Fe(0)- or Fe(II)-catalyzed dimerization reaction tolerates a wide range of functionalities, such as fluoro, chloro, bromo, alkenyl, nitrile, ether, ester, pyrrolyl, indolyl and carbazolyl groups, including cyclic and acyclic alkyls as well as an alkyl-bearing fatty-alcohol moiety. Especially, the coupling between two distinct isatins provided excellent selectivity for the cross-dimerization with trace of self-couplings. The single-crystal X-ray diffraction study established the molecular structure of eight dimerized products. A preliminary mechanistic study of the Fe-catalyzed dimerization supported the radical pathway for the reaction.
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http://dx.doi.org/10.1002/asia.202200414 | DOI Listing |
ACS Catal
September 2024
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
The synthesis and application of aryl-substituted pyridine(diimine) iron complexes (PDI)FeCH to the catalytic borylation of heteroarenes under thermal conditions is described. Improvements in catalyst design and performance were guided by precatalyst activation studies, where investigations into stoichiometric reactivities of iron borohydride (4- Bu- PDI)Fe(HBPin) and iron furyl (4- Bu- PDI)Fe(2-methylfuryl) complexes revealed facile C(sp)-H activation and a slower and potentially turnover-limiting C(sp)-B formation step. Formation of the flyover dimer, [(4- Bu- PDI)Fe] was identified as a catalyst deactivation pathway and formally iron(0) complexes were found to be inactive for borylation.
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August 2024
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
Iron gall ink (IGI), renowned for its indelibility, was the most important writing ink in the Western world from the 15th to the late 19th century. However, it is now known that IGIs induce acid-catalyzed hydrolysis and iron-catalyzed oxidation of the cellulose in historical paper documents. These mechanisms of deterioration cause significant damage to the writing support materials, including color alteration and burn-through appearance, and in the worst scenarios, physical disintegration of the supports.
View Article and Find Full Text PDFFront Ophthalmol (Lausanne)
December 2023
Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States.
Aim: Iron dysregulation in conjunction with other disease processes may exacerbate retinal degeneration. We employed models of iron overload and iron chelation to explore the interactions between iron-catalyzed oxidation and photoreactive bisretinoid lipofuscin.
Methods: The mice were injected intravitreally with ferric ammonium citrate (FAC) or were treated using the iron chelator deferiprone (DFP) from birth to 2 months of age.
Org Lett
February 2024
Chair of Organic Chemistry I, Faculty of Chemistry and Food Chemistry, TU Dresden, Bergstraße 66, DE-01069 Dresden, Germany.
We present a straightforward one-step process to access a range of novel -diindolepyrazines via an unprecedented [-BuN][Fe(CO)(NO)] (TBA[Fe])-catalyzed intermolecular nitrogenative dimerization of various indole derivatives. Remarkably, tosylazide functions as a N1-synthon forming the central pyrazine unit that joins the two indole subunits. The catalytic transformation shows a good substrate scope, and the obtained products show interesting electronic properties.
View Article and Find Full Text PDFChemistry
January 2024
Department of Chemistry, University of Illinois-Chicago, 845 West Taylor St, Chicago, IL 60607, USA.
We report the oxidative dimerization reaction of siloxydienes derived from simple enones that creates a new gamma-gamma (γ-γ) C-C bond using catalytic iron and benzoyl peroxide as the terminal oxidant in acetonitrile solvent at ambient temperature. The reaction shows a broad substrate scope including cyclic and acyclic siloxydienes derived from ketones, aldehydes, and esters, which are converted to 1,8-dicarbonyl compounds under mild catalytic reaction conditions in 19-89 % yield across 30 examples. The method is suitable for the coupling of sterically demanding carbon centers, including the formation of vicinal quaternary centers.
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