Enantioselective Friedel-Crafts reaction of acylpyrroles with glyoxylates catalyzed by BINOL-Ti(IV) complexes

Org Lett. 2011 Nov 18;13(22):5944-7. doi: 10.1021/ol202244u. Epub 2011 Oct 19.

Abstract

We report the first efficient enantioselective Friedel-Crafts hydroxyalkylation of pyrroles having one electron-withdrawing group at the α, β or N-positions with alkyl glyoxylates catalyzed by readily available chiral BINOL-Ti(IV) complexes (1-5 mol %). The reaction regioselectively led to the desired pyrrole-hydroxyacetic acid derivatives with good yields (70-96%) and enantiomeric excesses up to 96%, and is applicable in multigram scale with low loading of the catalyst (1 mol %).

MeSH terms

  • Catalysis
  • Glyoxylates / chemistry*
  • Molecular Structure
  • Naphthalenes / chemistry*
  • Pyrroles / chemistry*
  • Stereoisomerism
  • Titanium / chemistry*

Substances

  • Glyoxylates
  • Naphthalenes
  • Pyrroles
  • S(-)2,2'-dihydroxy-1,1'-binaphthyl
  • Titanium