Título:
|
Stereocontrolled annulations of indolo[2,3-a]quinolizidine-derived lactams with a silylated Nazarov reagent. Access to allo and epiallo yohimbine-type derivatives
|
Autor/a:
|
Arioli, Federica; Pérez Bosch, Maria; Are, Celeste; Estarellas, Carolina; Luque Garriga, F. Xavier; Bosch Cartes, Joan; Amat Tusón, Mercedes
|
Otros autores:
|
Universitat de Barcelona |
Abstract:
|
The facial selectivity of double Michael addition reactions of the silylated Nazarov reagent 4 to unsaturated indolo[2,3-a]quinolizidine lactams 3 has been studied. Pentacyclic 3-H/15-H trans adducts 5 are generated from Nind -unsubstituted lactams, but the corresponding cis isomers 6 are formed when the indole nitrogen has a tert-butyloxycarbonyl (Boc) substituent. This reversal in the facial selectivity of the annulation has been rationalized by means of theoretical calculations, which indicate that the initial nucleophilic attack under stereoelectronic control is hampered by the presence of the bulky Boc group. The synthetic usefulness of the pentacyclic Nazarov-derived adducts is demonstrated by their conversion into allo and epiallo yohimbine-type targets. |
Materia(s):
|
-Lactames -Alcaloides -Química orgànica -Lactams -Alkaloids -Organic chemistry |
Derechos:
|
(c) Wiley-VCH, 2015
|
Tipo de documento:
|
Artículo Artículo - Versión aceptada |
Editor:
|
Wiley-VCH
|
Compartir:
|
|