Stereoselective Polyglucuronic Acid Assembly via the Iron-Catalyzed Stereospecific Glycosylation with Glycal Epoxides

Polyglucuronic acids (PGAs) are directly involved in essential biological processes, but catalytic methods for stereoselective PGA synthesis are underdeveloped because glucuronic acid (GlcA) donors are intrinsically difficult to activate. We report herein a convergent and stereoselective PGA assembly method via iron-catalyzed iterative and stereospecific glycosylation with glycal epoxides. This method is effective in the assembly of an array of GlcA-β-1,4-GlcA linkages in complex glycans and readily provides PGA octasaccharides in high stereoselectivity.