An easy access to halide ion-catalytic alpha-glycosylation using carbon tetrabromide and triphenylphosphine as multifunctional reagents.
The reaction of a 2-O-benzyl-1-hydroxy sugar with CBr4 and Ph3P generates a glycosyl bromide in situ, which is coupled with an acceptor alcohol in the presence of N,N-tetramethylurea to afford an alpha-glycosyl product virtually quantitatively. In a proposed pathway, the reagent combination plays multiple roles such as the generation of a glycosyl donor, the activation of glycosylation, and the dehydration of the reaction system. These roles allow a simple alpha-glycosylation to be performed without special attention to dehydration. Various alpha-glycosyl (D-gluco-, D-galacto- and L-fuco-) products including glycosyl glycerols and cholesterols have been prepared with this method.
Shingu
Yuko
Y
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furou-chou, Chikusa-ku, Nagoya, 464-8603, Japan.
Nishida
Yoshihiro
Y
Dohi
Hirofumi
H
Kobayashi
Kazukiyo
K
D002784:Cholesterol / Q000031:analogs & derivatives / Q000138:chemical synthesis; D005990:Glycerol / Q000031:analogs & derivatives / Q000138:chemical synthesis; D006027:Glycosides / Q000138:chemical synthesis*; D006031:Glycosylation; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds / Q000737:chemistry*; D013402:Sugar Alcohols / Q000737:chemistry
D006027:Glycosides; D006842:Hydrocarbons, Brominated; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds; D013402:Sugar Alcohols; C061896:triphenylphosphine; D002784:Cholesterol; C031387:carbon tetrabromide; D005990:Glycerol