Exploiting the Strained Ion-Pair Interactions of Sterically Hindered Pyridinium Salts Toward SN2 Glycosylation of Glycosyl Trichloroacetimidates.
J Org Chem
; 89(6): 3713-3725, 2024 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-38407946
ABSTRACT
We demonstrate here that strained and sterically hindered protonated 2,4,6-tri-tert-butylpyridinium (TTBPy) tetrafluoroborate, a crystalline, bench stable salt serves as a mild and efficient organocatalyst for the SN2 type displacement of glycosyl trichloroacetimidates toward the stereoselective synthesis of both α- and ß-glycosides. The strained ion-pair interactions between the sterically hindered pyridinium cation and the tetrafluoroborate anion infuse unusual reactivity to the ions resulting in the unique anion assisted activation of alcohol. This mild activation of alcohol facilitates the SN2 type displacement of glycosyl α-trichloroacetimidates into ß-glycosides in a highly diastereoselective manner. These unique interactions were established based on extensive infrared and 1H, 19F, 11B NMR studies and theoretical studies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Org Chem
/
J. org. chem
/
Journal of organic chemistry
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Índia
País de publicação:
Estados Unidos