The development of a new bifunctional chiral primary amine thiourea catalyst and its application in the first asymmetric conjugate addition of oxindoles to enales was described. The reaction between 3-methyl oxindole and cinnamaldehyde, a combination of simple and readily available starting materials that targets in organic synthesis, was selected. The poor catalytic performance and the very low selectivity observed suggest a critical role of the thiourea moiety during the steroselective C-C bond-forming step. It is also found that by using 50% of benzoic acid, the catalyst loading is reduced to 10%, while still maintaining high diastero and enantiocontrol, and significant reactivity. The best diasterocontrol is observed for enals that have a naphthyl β substituted and by using oxindole that has a benzyl substitute.

Asymmetrie iminium ion catalysis with a novel bifunctional primary amine thiourea: Controlling adjacent quaternary and tertiary stereocenters

Pesciaioli F.;
2009-01-01

Abstract

The development of a new bifunctional chiral primary amine thiourea catalyst and its application in the first asymmetric conjugate addition of oxindoles to enales was described. The reaction between 3-methyl oxindole and cinnamaldehyde, a combination of simple and readily available starting materials that targets in organic synthesis, was selected. The poor catalytic performance and the very low selectivity observed suggest a critical role of the thiourea moiety during the steroselective C-C bond-forming step. It is also found that by using 50% of benzoic acid, the catalyst loading is reduced to 10%, while still maintaining high diastero and enantiocontrol, and significant reactivity. The best diasterocontrol is observed for enals that have a naphthyl β substituted and by using oxindole that has a benzyl substitute.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

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/11697/150194
Citazioni
  • ???jsp.display-item.citation.pmc??? 8
  • Scopus 162
  • ???jsp.display-item.citation.isi??? 159
social impact