An Expeditious Route to Streptococci and Enterococci Glycolipids Via Ring-Opening of 1,2-Anhydrosugars with Protic Acids
Titel:
An Expeditious Route to Streptococci and Enterococci Glycolipids Via Ring-Opening of 1,2-Anhydrosugars with Protic Acids
Auteur:
Timmers, C. M. van Straten, N. C. R. van der Marel, G. A. van Boom, J. H.
Verschenen in:
Journal of carbohydrate chemistry
Paginering:
Jaargang 17 (1998) nr. 3 pagina's 471-487
Jaar:
1998-04-01
Inhoud:
1,2-Anhydroglucose 6 reacts smoothly and with a high degree of stereoselectivity with a variety of carboxylic and phosphoric acids resulting in the formation of the predominantly β-oriented 1-O-acyl and 1-O-phosphorylglucoses 7-17. This methodology has been successfully applied in the construction of glycolipids 1a,b. Ring-opening of the 1,2-anhydroglucose derivative 19 with benzoic acid furnished exclusively the β-aligned key intermediate 20. Subsequent ICDT-assisted chemoselective α-glucosylation of 20 with thioethyl donor 21, followed by glycosidation of kojibiosyl benzoate 22 with glycerol acceptor 23 gave the fully protected α-diglucosyl glycerol derivative 25, which upon desilylation (→28), acylation (→29 or 30) and deprotection afforded the target glycolipids 1a-b in high overall yield.