Preparation of (2-naphthyl)methylene acetals of glycosides and their hydrogenolytic transformation into 2-naphthylmethyl (NAP) ethers

András Lipták, Anikó Borbás, Lóránt Jánossy, László Szilágyi

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33 Citations (Scopus)

Abstract

Dioxane- and dioxolane-type (2-naphthyl)methylene acetals of glycosides were prepared by acid-catalyzed transacetalization reactions. The acetals were cleaved using either AlH3 (LiAlH4:AlCl3-3:1), NaCNBH3-HCl or BH3·Me3N-AlCl3 reagents. Reaction of the 4,6-O-acetals with AlH 3 yielded 4-ONAP ethers whereas the other two reagents gave 6-ONAP derivatives with excellent regioselectivity. In dioxolane, type acetals the direction of the cleavage with all three reagents is determined by the stereochemistry of the acetal center; equatorial ONAP/axial-hydroxy derivatives are obtained from the exo-naphthyl isomers; endo-naphthyl acetals, on the other hand, give rise to the formation of axial ONAP/equatorial-hydroxy compounds. The NAP ether and the (2-naphthyl)methylene acetal protecting groups can both be readily removed by treatment with DDQ. (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)4949-4953
Number of pages5
JournalTetrahedron Letters
Volume41
Issue number25
DOIs
Publication statusPublished - Jun 19 2000

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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