A hexameric resorcinarene capsule acts as a hydrogen bonding catalyst for the activation of encapsulated nitroalkenes toward the addition of pyrroles and indoles. Once inside the capsule (C), β-nitrostyrene 3a establishes H-bonding interactions with the bridging water molecules having free H-bond-donating valences. Thus, the activation of nitroalkenes favors the conjugate addition of pyrroles and indoles. It is demonstrated that the inherent acidity of capsule C is sufficient to promote the Michael-type Friedel–Crafts (MTFC) reaction under the mild reaction conditions described herein. In silico calculations point out the catalytically relevant role of the bridging water molecules of C and confirm the supramolecular control exerted by the capsule, which protects the nitronic acid intermediate with respect to the degradation pathway that commonly occurs in the bulk medium.

A hexameric resorcinarene capsule as a hydrogen bonding catalyst in the conjugate addition of pyrroles and indoles to nitroalkenes

Gambaro, Stefania;De Rosa, Margherita
;
Soriente, Annunziata;Talotta, Carmen;Gaeta, Carmine;Neri, Placido
2019

Abstract

A hexameric resorcinarene capsule acts as a hydrogen bonding catalyst for the activation of encapsulated nitroalkenes toward the addition of pyrroles and indoles. Once inside the capsule (C), β-nitrostyrene 3a establishes H-bonding interactions with the bridging water molecules having free H-bond-donating valences. Thus, the activation of nitroalkenes favors the conjugate addition of pyrroles and indoles. It is demonstrated that the inherent acidity of capsule C is sufficient to promote the Michael-type Friedel–Crafts (MTFC) reaction under the mild reaction conditions described herein. In silico calculations point out the catalytically relevant role of the bridging water molecules of C and confirm the supramolecular control exerted by the capsule, which protects the nitronic acid intermediate with respect to the degradation pathway that commonly occurs in the bulk medium.
File in questo prodotto:
File Dimensione Formato  
The Hexameric Resorcinarene Capsule as a Hydrogen Bonding Catalyst in the Conjugate Addition of Pyrroles and Indoles to Nitroalkenes _accepted version.pdf

embargo fino al 01/05/2020

Descrizione: Manuscript _accepted version
Tipologia: Documento in Post-print (versione successiva alla peer review e accettata per la pubblicazione)
Licenza: Creative commons
Dimensione 819.54 kB
Formato Adobe PDF
819.54 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4726134
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 18
  • ???jsp.display-item.citation.isi??? 18
social impact