Bismuth triflate-catalyzed Wagner-Meerwein rearrangement in terpenes. Application to the synthesis of the 18alpha-oleanane core and A-neo-18alpha-oleanene compounds from lupanes.
Org Biomol Chem
; 7(3): 508-17, 2009 Feb 07.
Article
em En
| MEDLINE
| ID: mdl-19156317
ABSTRACT
The use of bismuth(III) salts as catalysts for the Wagner-Meerwein rearrangement of lupane derivatives with expansion of ring E and formation of an additional O-containing ring is reported. This process has also been extended to other terpenes, such as the sesquiterpene (-)-caryophyllene oxide. When the reaction was performed with oleanonic acid, 28,13beta-lactonization occurred, without Wagner-Meerwein rearrangement. Under more vigorous reaction conditions, dehydration of the 3beta-hydroxyl group and subsequent additional Wagner-Meerwein rearrangement led to the selective synthesis of A-neo-18alpha-oleanene compounds, in very high yields.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ácido Oleanólico
/
Terpenos
/
Triterpenos
/
Mesilatos
Idioma:
En
Revista:
Org Biomol Chem
Assunto da revista:
BIOQUIMICA
/
QUIMICA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Portugal