β-(2-Aminophenyl)-α,β-ynones afforded 3-unsubstituted 2-acylindoles in good yields in the presence of 20 mol % AgOTf under (microwave) MW heating. The use CuOTf as a catalyst resulted in a similar reaction outcome, generally with a lower efficiency. This transformation represents the first example of 5-endo-dig cyclization of 2-alkynylanilines bearing an acyl group linked to the triple bond. By contrast with the previously reported gold-catalyzed reaction of β-(2-aminophenyl)-α,β-ynones, which resulted in the formation of dibenzo[1,5]diazocines through a sequential process triggered by an intermolecular hydroamination, a selective intramolecular anti-Michael hydroamination was observed in the present study by silver/copper catalysis. Density functional theory calculations on the Ag-catalyzed reaction revealed that the catalyst induces an electrostatic arrangement in the TS coherent with the experimentally observed cyclization.

Synthesis of 2‑Acylindoles via Ag- and Cu-Catalyzed anti-Michael Hydroamination of β‑(2-Aminophenyl)-α,β-ynones: Experimental Results and DFT Calculations.

Navnath D. Rode
Membro del Collaboration Group
;
Issam Abdalghani
Membro del Collaboration Group
;
Antonio Arcadi
Membro del Collaboration Group
;
Massimiliano Aschi
Membro del Collaboration Group
;
Marco Chiarini
Membro del Collaboration Group
;
Fabio Marinelli
Writing – Original Draft Preparation
2018-01-01

Abstract

β-(2-Aminophenyl)-α,β-ynones afforded 3-unsubstituted 2-acylindoles in good yields in the presence of 20 mol % AgOTf under (microwave) MW heating. The use CuOTf as a catalyst resulted in a similar reaction outcome, generally with a lower efficiency. This transformation represents the first example of 5-endo-dig cyclization of 2-alkynylanilines bearing an acyl group linked to the triple bond. By contrast with the previously reported gold-catalyzed reaction of β-(2-aminophenyl)-α,β-ynones, which resulted in the formation of dibenzo[1,5]diazocines through a sequential process triggered by an intermolecular hydroamination, a selective intramolecular anti-Michael hydroamination was observed in the present study by silver/copper catalysis. Density functional theory calculations on the Ag-catalyzed reaction revealed that the catalyst induces an electrostatic arrangement in the TS coherent with the experimentally observed cyclization.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/127081
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