1-Chloro-2,3-diphenylcyclopropenium ion was found to be a very efficient organocatalyst (3 mol% loading) for liquid phase Beckmann rearrangement of various ketoximes to the corresponding amides/lactams within 2 h in acetonitrile at reflux temperature. This is the first example of the application of the cyclopropenium ion as a catalyst, which opens up a new aspect of the synthetic utility of aromatic cation based catalysis.
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http://dx.doi.org/10.1039/c0cc00815j | DOI Listing |
Chem Sci
September 2023
South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology Guangzhou 510640 China
Exploring new noncovalent synthons for supramolecular assembly is essential for material innovation. Accordingly, we herein report a unique type of cyclopropenium-based supramolecular motif and demonstrate its applications to polymer self-assembly. Because of the "ion pair strain" effect, trisaminocyclopropenium iodides complex strongly with fluoroiodobenzene derivatives, forming stable adducts.
View Article and Find Full Text PDFNat Commun
August 2023
Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, OH, 45221, USA.
Lithium-based nonaqueous redox flow batteries (LRFBs) are alternative systems to conventional aqueous redox flow batteries because of their higher operating voltage and theoretical energy density. However, the use of ion-selective membranes limits the large-scale applicability of LRFBs. Here, we report high-voltage membrane-free LRFBs based on an all-organic biphasic system that uses Li metal anode and 2,4,6-tri-(1-cyclohexyloxy-4-imino-2,2,6,6-tetramethylpiperidine)-1,3,5-triazine (Tri-TEMPO), N-propyl phenothiazine (C3-PTZ), and tris(dialkylamino)cyclopropenium (CP) cathodes.
View Article and Find Full Text PDFJ Am Chem Soc
August 2023
Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
Herein, we disclose an approach to synthesize -alkyl cyclopropanes by leveraging C-F bond functionalization of -difluorocyclopropenes using tris(pentafluorophenyl)borane catalysis. The reaction proceeds through the intermediacy of a fluorocyclopropenium ion, which was confirmed by the isolation of [Ph(CD)C][(CF)BF]. We found that silylketene acetal nucleophiles were optimal reaction partners with fluorocyclopropenium ion intermediates yielding fully substituted cyclopropenes functionalized with two α--alkyl centers (63-93% yield).
View Article and Find Full Text PDFAcc Chem Res
October 2022
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
Cyclopropenium ions are the smallest class of aromatic compounds, satisfying Hückel's rules of aromaticity with two π electrons within a three-membered ring. First prepared by Breslow in 1957, cyclopropenium ions have been found to possess extraordinary stability despite being both cationic and highly strained. In the 65 years since their first preparation, cyclopropenium ions have been the subject of innumerable studies concerning their synthesis, physical properties, and reactivity.
View Article and Find Full Text PDFNanomaterials (Basel)
September 2021
Hebei Key Laboratory of Functional Polymers, Department of Polymer Materials and Engineering, Hebei University of Technology, 8 Guangrong Street, Tianjin 300130, China.
The development of solid-state polymer electrolytes is an effective way to overcome the notorious shuttle effect of polysulfides in traditional liquid lithium sulfur batteries. In this paper, cationic cyclopropenium based cross-linked polymer was firstly prepared with the one pot method, and then the counter ion was replaced by TFSI anion using simple ion replacement. Cationic cyclopropenium hyper-crosslinked polymer (HP) was introduced into a polyethylene oxide (PEO) matrix with the solution casting method to prepare a composite polymer electrolyte membrane.
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