"Ring opening-ring closure" strategy for the synthesis of aryl-C-glycosides

J Org Chem. 2014 May 16;79(10):4676-86. doi: 10.1021/jo500730y. Epub 2014 May 5.

Abstract

A new "ring-opening-ring closure" strategy for the synthesis of aryl-C-glycosides was described. This strategy exploited the nickel-catalyzed regioselective β-O elimination of glycals by reactions with various aryl boronic acids or potassium aryltrifluoroborates to yield the ring-opened products, which underwent the Lewis acid, protonic acid, PhSeCl, or NBS mediated ring closure reactions to afford diverse aryl-C-glycosides. After Lewis acids and protonic acids were screened, it was found that, starting from the ring-opened substrates, the Ph3PHBr or Sc(OTf)3 mediated ring closure reaction provided α- or β-preferred aryl-C-Δ(2,3)-glycosides, respectively. Furthermore, β-D-phenyl-C-glycosides were successfully prepared via the PhSeCl-mediated cyclization reaction, whereas the α-D-phenyl-C-glycoside was obtained via the NBS-mediated cyclization reaction. After removal of the 2-substituted functionalities by Bu3SnH/AIBN, the synthesis of 2-deoxy-aryl-C-glycosides was ultimately realized in a stereoselective manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclization
  • Glycosides / chemical synthesis*
  • Glycosides / chemistry*
  • Lewis Acids / chemistry*
  • Molecular Structure
  • Monosaccharides / chemical synthesis*
  • Monosaccharides / chemistry*
  • Stereoisomerism

Substances

  • C-glycoside
  • Glycosides
  • Lewis Acids
  • Monosaccharides