title: Organoboron-Promoted Regioselective Glycosylations in the Synthesis of a Saponin-Derived Pentasaccharide from Spergularia ramosa.
abstract: Organoboron-mediated regioselective glycosylations were employed as key steps in the total synthesis of a branched pentasaccharide from a saponin natural product. The ability to use organoboron activation to differentiate OH groups in an unprotected glycosyl acceptor, followed by substrate-controlled reactions of the obtained disaccharide, enabled a streamlining of the synthesis relative to a protective group-based approach. This study revealed a matching/mismatching effect of the relative configuration of donor and acceptor on the efficiency of a regioselective glycosylation reaction, a problem that was solved through the development of a novel boronic acid-amine copromoter system for glycosyl acceptor activation.
authors: Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, ON M5S 3H6, Canada.
authors: Ross S
authors: RS
authors: Mancini
authors: Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, ON M5S 3H6, Canada.
authors: Corey A
authors: CA
authors: McClary
authors: Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, ON M5S 3H6, Canada.
authors: Stefi
authors: S
authors: Anthonipillai
authors: Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, ON M5S 3H6, Canada.
authors: Mark S
authors: MS
authors: Taylor
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D002240:Carbohydrate Sequence; D029748:Caryophyllaceae / Q000737:chemistry*; D006031:Glycosylation; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D012503:Saponins / Q000737:chemistry*
chemical_list: D001896:Boron Compounds; D009844:Oligosaccharides; D012503:Saponins