Author
Tamás Hergert
Bio: Tamás Hergert is an academic researcher from Budapest University of Technology and Economics. The author has contributed to research in topics: Halogenation & Conjugated system. The author has an hindex of 3, co-authored 7 publications receiving 36 citations.
Papers
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TL;DR: The findings that Tf2O-mediated amide activation is obstructed by the easy protonation of amides by the formed triflic acid during the activation step are reported.
Abstract: An efficient synthesis has been developed for the preparation of 9H-pyrrolo[1,2-a]indol-9-ones (fluorazones) from readily available anthranilic acid derivatives via a one-pot amide- and pyrrole-formation step, followed by an intramolecular cyclodehydration. The cyclodehydration process is mediated by the activation of aromatic tertiary amides by triflic anhydride (Tf2O). Comparison of various benzo-substituents is shown to demonstrate the high functional group tolerance of this transformation. In addition, study of the reaction mechanism is also presented to unfold the exact role of the applied base additive. Herein, as a first example, we report our findings that Tf2O-mediated amide activation is obstructed by the easy protonation of amides by the formed triflic acid during the activation step. Additionally, it has been also proven that the base additive is not involved in the transformation of O-triflyliminium triflates into reactive species (e.g., nitrilium triflates) and is only responsible to neutralize the superacid to avoid the protonation of both the secondary or tertiary amides.
18 citations
TL;DR: In this article, a synthetic sequence for the preparation of fully conjugated, 2,7-disubstituted fluorazone derivatives was developed, comprising Elming-Clauson-Kaas type pyrrole formation, POCl3-mediated ring closure, selective halogenation and elongation of the conjugate backbone via cross-coupling reactions.
14 citations
TL;DR: In this paper, an efficient regioselective synthesis for the preparation of 5-(diphenylmethylene)-1H-pyrrol-2(5H)-ones by sequential dibromination and selective organometallic bromine/lithium exchange followed by reaction with benzophenone was developed.
8 citations
TL;DR: In this paper, a method for the preparation of 1,3-dioxolane-protected 5-arylthiophene-2-carboxaldehydes via a one-pot borylation-copper(I) chloride co-catalyzed Suzuki-Miyaura coupling reaction is described.
4 citations
TL;DR: In this article, a comparative study of two regioisomeric series of atropisomerics amino alcohols and their application in the enantio-selective addition of diethylzinc to benzaldehyde is reported.
Abstract: Syntheses of two regioisomeric series of atropisomeric amino alcohols and a comparative study on their application in the enantioselective addition of diethylzinc to benzaldehyde are reported. Systematic modification of the electronic and steric properties of the functional groups resulted in highly efficient catalyst ligands in both series. Quantum-chemical calculations agreed well with the experimental results of this first systematic comparative study on regioisomeric atropisomeric ligands.
3 citations
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TL;DR: A stable organic semiconductor material, mesoporous graphitic carbon nitride (mpg-CN), can act as a visible-light photoredox catalyst to orchestrate oxidative and reductive interfacial electron transfers to two different substrates in a two- or three-component system for direct twofold carbon–hydrogen functionalization of arenes and heteroarenes.
Abstract: Photoexcited electron-hole pairs on a semiconductor surface can engage in redox reactions with two different substrates. Similar to conventional electrosynthesis, the primary redox intermediates afford only separate oxidized and reduced products or, more rarely, combine to one addition product. Here, we report that a stable organic semiconductor material, mesoporous graphitic carbon nitride (mpg-CN), can act as a visible-light photoredox catalyst to orchestrate oxidative and reductive interfacial electron transfers to two different substrates in a two- or three-component system for direct twofold carbon-hydrogen functionalization of arenes and heteroarenes. The mpg-CN catalyst tolerates reactive radicals and strong nucleophiles, is straightforwardly recoverable by simple centrifugation of reaction mixtures, and is reusable for at least four catalytic transformations with conserved activity.
348 citations
TL;DR: The advancements (within the last 4 years) in catalysis related to SMCR that would be beneficial for researchers in designing synthetic protocols for the preparation of pharmacophores as well as drug molecules are discussed.
68 citations
TL;DR: DFT calculations elucidate the origins of the observed excellent atroposelectivity in N‐arylpyrroles and reveal the synthetic utility of this new method.
Abstract: A transformation of fluxional into configurationally stable axially chiral N-arylpyrroles was achieved with a highly atroposelective electrophilic aromatic substitution catalyzed by a chiral-at-metal rhodium Lewis acid. Specifically, N-arylpyrroles were alkylated with N-acryloyl-1H-pyrazole electrophiles in up to 93 % yield and with up to >99.5 % ee, and follow-up conversions reveal the synthetic utility of this new method. DFT calculations elucidate the origins of the observed excellent atroposelectivity.
49 citations
40 citations
TL;DR: This article provides a complete, up-to-date review of pyrrole-containing semiconducting materials used for organic photovoltaics and organic field-effect transistors and highlight recent advances in the synthesis of these materials.
Abstract: Organic semiconducting materials derived from π-electron-rich pyrroles have garnered attention in recent years for the development of organic semiconductors Although pyrrole is the most electron-r
39 citations