Iodine-Catalyzed Nazarov Cyclizations.
J Org Chem
; 84(12): 7587-7605, 2019 Jun 21.
Article
em En
| MEDLINE
| ID: mdl-31188597
ABSTRACT
The Nazarov cyclization is an important pericyclic reaction that allows the synthesis of substituted cyclopentenones. We now demonstrate that this reaction can be performed under very mild, metal-free reaction conditions using molecular iodine as the catalyst. A variety of different divinyl ketones including aromatic systems undergo the iodine-catalyzed reaction with moderate to very good yields in both polar and apolar solvents. Our mechanistic studies indicate that the Nazarov system is activated through a halogen bond between the carbonyl group and the catalyst, and other modes of action like Brønsted acid or iodonium ion catalysis are unlikely. Furthermore, addition of iodine to the double bond or a putative iodine-catalyzed cis- trans isomerization of the employed olefins seem not to be an important side reaction here.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Alemanha