Subscribe to RSS
DOI: 10.1055/s-0028-1083590
Saturated C-Glycosides via Ni-Catalyzed Diastereoselective Cross-Coupling
Contributor(s):Paul Knochel, Andreas J. WagnerUniversity of North Carolina at Chapel Hill, USA
Diastereoselective Ni-Catalyzed Negishi Cross-Coupling Approach to Saturated, Fully Oxygenated C-Alkyl and C-Aryl Glycosides
J. Am. Chem. Soc. 2008, 130: 12177-12183
Publication History
Publication Date:
20 November 2008 (online)
Key words
glycosides - Negishi reaction - nickel - diastereoselectivity
Significance
A Ni-catalyzed Negishi cross-coupling leading to C-glycosides is described. NiCl2/PyBox in dimethylimidazolidinone (DMI) efficiently enables the synthesis of C-alkyl glycosides whereas for arylation the combination of Ni(cod)2/tert-Bu-terpy in DMF is more effective. While the reaction proceeds in moderate yields and β-selectivity for glucose derivatives, it is high-yielding and β-selective for mannosides.
Comment
This Negishi protocol on sugar derivatives displays outstanding functional group tolerance. The authors have demonstrated that existing Ni-catalyzed Negishi coupling methodologies can be adapted to the stereoselective synthesis of C-alkyl and C-aryl glycosides using various alkyl- and arylzinc reagents in overall high yields. A suitable choice of the triaza ligands leads to high α- or β-selectivities for glucosides and mannosides, respectively.