- Palladium-Catalyzed Aminocyclization-Coupling Cascades: Preparation of Dehydrotryptophan Derivatives and Computational Study
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Dehydrotryptophan derivatives have been prepared by palladium-catalyzed aminocyclization-Heck-type coupling cascades starting from o-alkynylaniline derivatives and methyl α-aminoacrylate. Aryl, alkyl (primary, secondary, and tertiary), and alkenyl substituents have been introduced at the indole C-2 position. Further variations at the indole benzene ring, as well as the C-2-unsubstituted case, have all been demonstrated. In the case of C-2 aryl substitution, the preparation of the o-alkynylaniline substrate by Sonogashira coupling and the subsequent cyclization-coupling cascade have been performed in a one-pot protocol with a single catalyst. DFT calculations have revealed significant differences in the reaction profiles of these reactions relative to those involving methyl acrylate or methacrylate, and between the reactions of the free anilines and their corresponding carbamates. Those calculations suggest that the nature of the alkene and of the acid HX released in the HX/alkene exchange step that precedes C-C bond formation could be responsible for the experimentally observed differences in reaction efficiencies.
- Vaz, Belén,Martínez, Claudio,Cruz, Francisco,Denis, J. Gabriel,De Lera, ángel R.,Aurrecoechea, José M.,álvarez, Rosana
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p. 8766 - 8785
(2021/06/30)
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- Nickel(II)- And Silver(I)-Catalyzed C-H Bond Halogenation of Anilides and Carbamates
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ortho -C-H bond halogenation of anilides and N -aryl carbamates using easily available N -halosuccinimides (NXS) as the active halogenation reagent in the presence of nickel or silver catalyst has been developed. This method provides a new approach to 2-haloanilides and carbamates, which may serve as starting materials for the synthesis of pharmaceutically and biologically active compounds.
- Kianmehr, Ebrahim,Afaridoun, Hadi
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p. 1513 - 1523
(2020/12/14)
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- Synthesis of 7-alkylidene-7,12-dihydroindolo[3,2-d]benzazepine-6-(5H)-ones (7-alkylidene-paullones) by N-cyclization-oxidative Heck cascade and characterization as sirtuin modulators
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An extension of our reported protocol to benzofused heterocyclic derivatives (benzofurans, indoles, isochromeneimines), involving a palladium-induced cascade of N-cyclization and oxidative Heck reactions of o-alkynylanilines, has allowed the preparation o
- Denis,Franci,Altucci,Aurrecoechea,De Lera,lvarez
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p. 2800 - 2810
(2015/04/21)
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- Facile double-lithiation of a transient urea: Vicarious ortho -metalation of aniline derivatives
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A convenient one-pot method for the conversion of phenylisocyanate into ortho-functionalized aniline derivatives has been developed. The reaction proceeds via the selective ortho-metalation of a transient labile urea, which can be considered as a synthetic equivalent of 2-lithio-phenylisocyanate, a highly improbable intermediate.
- Houlden, Chris E.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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supporting information; experimental part
p. 3090 - 3092
(2010/09/05)
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- Synthesis of 2-quinolones via palladium-catalyzed carbonylative annulation of internal alkynes by N-substituted o-iodoanilines
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The palladium-catalyzed annulation of internal alkynes by N-substituted o-iodoanilines under 1 atm of carbon monoxide results in the formation of 3,4-disubstituted 2-quinolones. The nature of the substituent on the nitrogen is crucial to obtaining high yields of 2-quinolones. The best results are obtained using alkoxycarbonyl, p-tolylsulfonyl, and trifluoroacetyl substituents. The nitrogen substituent is lost during the course of the reaction resulting in the formation of N-unsubstituted 2-quinolones. A variety of internal alkynes, bearing alkyl, aryl, heteroaryl, hydroxyl, and alkoxyl substituents, are effective in this process. Electron-rich and electron-poor N-substituted o-iodoanilines, as well as heterocyclic analogues, can be employed as annulating agents.
- Kadnikov, Dmitry V.,Larock, Richard C.
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p. 6772 - 6780
(2007/10/03)
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