Acid treatment of indole-2-carboxylic acid b- and g-oxoamides causes Friedel–Crafts intramolecular cyclization to b-carbolinones and dihydro-2H-azepino[3,4-b]indol-1-ones, in contrast to secondary d-,3-, and z-oxoamides, which cyclize to the novel heterocyclic rings pyrrolizino[2,1-b]indole, indolizino[2,1-b]indole, and 9a,11-diaza-indeno[1,2-a]azulene, via an intermediate N-acyliminium ion. Tertiary amides lead only the Friedel–Crafts ring closure, thus allowing the synthesis of larger fused rings.
Intramolecular N-acyliminium ion versus Friedel-Crafts cyclization onto 3-indoles : synthesis of the novel rings pyrrolizino[2,1-b]indole and homologues / R. Cincinelli, S. Dallavalle, L. Merlini, R. Nannei, L. Scaglioni. - In: TETRAHEDRON. - ISSN 0040-4020. - 65:17(2009), pp. 3465-3472.
Titolo: | Intramolecular N-acyliminium ion versus Friedel-Crafts cyclization onto 3-indoles : synthesis of the novel rings pyrrolizino[2,1-b]indole and homologues |
Autori: | CINCINELLI, RAFFAELLA (Primo) DALLAVALLE, SABRINA (Secondo) NANNEI, RAFFAELLA (Penultimo) SCAGLIONI, LEONARDO (Ultimo) |
Settore Scientifico Disciplinare: | Settore CHIM/06 - Chimica Organica |
Data di pubblicazione: | 2009 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1016/j.tet.2009.02.036 |
Appare nelle tipologie: | 01 - Articolo su periodico |