Synthesis and reactivity of 4'-deoxypentenosyl disaccharides.

ABSTRACT: 4-Deoxypentenosides (4-DPs) are versatile synthons for rare or higher-order pyranosides, and they provide an entry for structural diversification at the C5 position. Previous studies have shown that 4-DPs undergo stereocontrolled DMDO oxidation; subsequent epoxide ring-openings with various nucleophiles can proceed with both anti or syn selectivity. Here, we report the synthesis of ?- and ?-linked 4'-deoxypentenosyl (4'-DP) disaccharides, and we investigate their post-glycosylational C5' additions using the DMDO oxidation/ring-opening sequence. The ?-linked 4'-DP disaccharides were synthesized by coupling thiophenyl 4-DP donors with glycosyl acceptors using BSP/Tf2O activation, whereas ?-linked 4'-DP disaccharides were generated by the decarboxylative elimination of glucuronyl disaccharides under microwave conditions. Both ?- and ?-linked 4'-DP disaccharides could be epoxidized with high stereoselectivity using DMDO. In some cases, the ?-epoxypentenosides could be successfully converted into terminal l-iduronic acids via the syn addition of 2-furylzinc bromide. These studies support a novel approach to oligosaccharide synthesis, in which the stereochemical configuration of the terminal 4'-DP unit is established at a post-glycosylative stage.

SUBMITTER: Padungros P 

PROVIDER: S-EPMC4059249 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature