β-Anilinoacrylate Aspidosperma alkaloids vincadifformine (2a) and tabersonine (2b) react with Fremy's salt in aqueous acidic conditions via radical coupling at C-16. The resulting zwitterionic compounds 7a and 10 rearrange to isoxazolidines 8 and then ultimately to azepino[2,3-b]indoles 9. The mechanism of these reactions is discussed, and the structures of 7a, 8b, and 9a were established by single-crystal X-ray analysis. Diazotization of amine 20b (X = NH2) affords fragmentation-cyclization products corresponding to eburnanes 18 and 21. This reaction mimics the skeletal rearrangement of Aspidosperma → Hunteria alkaloids, and these findings support Wenkert's biogenetic proposal.

OXIDATION OF BETA-ANILINOACRYLATE ALKALOIDS VINCADIFFORMINE AND TABERSONINE BY FREMY SALT - A MECHANISTIC INSIGHT INTO THE REARRANGEMENT OF ASPIDOSPERMA TO HUNTERIA ALKALOIDS / G. PALMISANO, B. DANIELI, G. LESMA, F. TRUPIANO, T. PILATI. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 53:5(1988), pp. 1056-1064. [10.1021/jo00240a023]

OXIDATION OF BETA-ANILINOACRYLATE ALKALOIDS VINCADIFFORMINE AND TABERSONINE BY FREMY SALT - A MECHANISTIC INSIGHT INTO THE REARRANGEMENT OF ASPIDOSPERMA TO HUNTERIA ALKALOIDS

B. DANIELI;G. LESMA;
1988

Abstract

β-Anilinoacrylate Aspidosperma alkaloids vincadifformine (2a) and tabersonine (2b) react with Fremy's salt in aqueous acidic conditions via radical coupling at C-16. The resulting zwitterionic compounds 7a and 10 rearrange to isoxazolidines 8 and then ultimately to azepino[2,3-b]indoles 9. The mechanism of these reactions is discussed, and the structures of 7a, 8b, and 9a were established by single-crystal X-ray analysis. Diazotization of amine 20b (X = NH2) affords fragmentation-cyclization products corresponding to eburnanes 18 and 21. This reaction mimics the skeletal rearrangement of Aspidosperma → Hunteria alkaloids, and these findings support Wenkert's biogenetic proposal.
Settore CHIM/06 - Chimica Organica
JOURNAL OF ORGANIC CHEMISTRY
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento 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: http://hdl.handle.net/2434/183726
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 23
  • ???jsp.display-item.citation.isi??? 16
social impact