One-pot α-glycosylation pathway via the generation in situ of α-glycopyranosyl imidates in N,N-dimethylformamide

Yuko Shingu, Akira Miyachi, Yoshiko Miura, Kazukiyo Kobayashi, Yoshihiro Nishida

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Divergent pathways are disclosed in the activation of 2-O-benzyl-1-hydroxy sugars by a reagent combination of CBr4 and Ph3P, all of which afford one-pot α-glycosylation methods. When this reagent is used in CH2Cl2, the 1-hydroxy sugar is converted to the α-glycosyl bromide in a conventional way and leads to the one-pot α-glycosylation method based on a halide ion-catalytic mechanism. In either DMF or a mixture of DMF and CHCl3, however, alternative α-glycosyl species are generated. From the 1H and 13C NMR study of the products, as well as the reactions using Vilsmeier reagents [(CH3)2N+CHX]X- (X = Br and Cl), these were identified as cationic α-glycopyranosyl imidates having either Br- or Cl- counter ion. The cationic α-glycosyl imidate (Br-), derived specifically in the presence of DMF, is more reactive than the α-glycosyl bromide and thus is responsible for the accelerated one-pot α-glycosylation. The one-pot α-glycosylation methodology performed in DMF was assessed also with different types of acceptor substrates including tertiary alcohols and an anomeric mixture of 1-OH sugars.

Original languageEnglish
Pages (from-to)2236-2244
Number of pages9
JournalCarbohydrate Research
Volume340
Issue number14
DOIs
Publication statusPublished - Oct 17 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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