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2002 Fiscal Year Final Research Report Summary

Regioselective Glycosylation of Non-protected Methyl Hexopyranosides Using the Stannylene Activation Method

Research Project

Project/Area Number 12672059
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Chemical pharmacy
Research InstitutionKitasato University

Principal Investigator

KAJI Eisuke  Kitasato University, School of Pharmaceutical Sciences, Professor, 薬学部, 教授 (60050598)

Co-Investigator(Kenkyū-buntansha) HIROTANI Seiko  Assistant, 薬学部, 助手 (20050594)
YAGO Kazuo  Professor, 薬学部, 教授 (10276157)
Project Period (FY) 2000 – 2002
Keywordsglycosylation / oligosaccharide / dibutyltin oxide / Stannylene acetal / sugar hydroxyl group / Ag(I) silica alumina / glycosyl bromide / regioselectivity
Research Abstract

Developing a new method for regioselective glycosylation of unprotected sugars is highly desired, since the conventional protection-deprotection method renders the overall synthetic scheme lengthy and impractical. Chemical reactions should be much more selective, rapid, and productive.
In this context, very few precedents have revealed that the stannylene-mediated regioselective glycosylation of unprotected hexopyranosides makes it possible to provide one-pot assembly of some oligosaccharides. However, the previous methods were limited to afford α / β-(1 → 6)-linked disaccharides only, I.e., glycosylation of the primary hydroxyl group of hexoses is preferred, and the yields of the glycosylation reaction are not always high. Therefore, it is necessary to develop a novel regioselective glycosylation applicable to the secondary hydroxyl groups even in the presence of the primary hydroxyl one, giving for example, α / β-(1→3)-linked disaccharides.
We have developed a novel methodology of regio- and stereoselective glycosylation for fully unprotected methyl hexopyranosides by the stannylene activation method. Ag(I)-silica alumina-promoted glycosylation of stannylated sugars in the one-pot process was shown to yield β-(1 → 6)-linked disaccharides predominantly. Furthermore, addition of some tetra butylammonium salts to the reaction medium provides a significant regioselectivity shift on the glycosylation of unprotected methyl β-D-galactopyranoside, affording glucosyl-β-(1 → 3) -galactoside in preference to the corresponding β-(1→6)-linked disaccharide.
Since glycosyl β-(1→ 3)-galactoside moiety is well known as a core disaccharide unit of many immunologically relevant oligosaccharides, the method reported here would contribute to synthetic carbohydrate chemistry, which can be an alternative to the conventional "protection-deprotection" method.

  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] E.Kaji, N.Harita: "Stannylene Acetal-Mediated Regioselective Open Glyco-sylation of Methyl β-D-Galactopyranoside"Tetrahedron Letters. 41. 53-56 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E.Kaji, K.Shibayama, K.In: "Regioselectivity shift from β(1→6)-to β(1→3)-Glycosylation of Non-protected Methyl β-D-Galactopyranoside"Tetrahedron Letters. 44(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E.Kaji, K.Harita: "Stannylene Acetal-Mediated Regioselective Open Glycosylation of Methyl β-D-Galacto-pyranoside and Methyl α-L-Rhamnopyranoside"Tetrahedron Lett.. Vol.41. 53-56 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E.Kaji, K.Shibayama, K.In: "Regioselectivity Shift from β-(1→6)- to β-(1→3)-Glycosylation of Non-protected Methyl β-D-Galactopyranoside Using the Stannylene Activation Method"Tetrahedron Lett.. Vol.44, in press. (2003)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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