Carbene-mediated functionalization of the anomeric C-H bond of carbohydrates: scope and limitations.
Chemistry
; 19(19): 6052-66, 2013 May 03.
Article
em En
| MEDLINE
| ID: mdl-23418074
ABSTRACT
Herein we investigate the scope and limitations of a new synthetic approach towards α- and ß-ketopyranosides relying on the functionalization of the anomeric C-H bond of carbohydrates by insertion of a metal carbene. A key bromoacetate grafted at the 2-position is the cornerstone of a stereoselective glycosylation/diazotransfer/quaternarization sequence that makes possible the construction of a quaternary center with complete control of the stereochemistry. This sequence shows a good tolerance toward protecting groups commonly used in carbohydrate chemistry and gives rise to quaternary disaccharides with good efficiency. In the case of a disaccharide with a more restricted conformation, this functionalization process can be hampered by the steric demand next to the targeted anomeric position. In addition, the formation of transient orthoesters during the glycosylation step may also reduce the overall efficiency of the synthetic sequence.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ródio
/
Carboidratos
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Dissacarídeos
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Glicosídeos
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Metano
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article