Synthesis of 5-iodopyrrolo[1,2-a]quinolines and indolo[1,2-a]quinolines via iodine-mediated electrophilic and regioselective 6-endo-dig ring closure

J Org Chem. 2011 Jul 15;76(14):5670-84. doi: 10.1021/jo200638k. Epub 2011 Jun 16.

Abstract

The endo-cyclic ring closure of 1-(2-(substituted ethynyl)phenyl)-1H-pyrroles 3a-t and 1-(2-(substituted ethynyl)phenyl)-H-indole 4a-o mediated by Lewis acid (I(2)) under mild conditions afforded substituted 5-iodopyrrolo[1,2-a]quinolines 5a-t and 5-iodoindolo[1,2-a]quinolines 6a-o in good to excellent yields. The reaction shows selective C-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-dig-cyclized product. Iodo derivatives of pyrrolo- and indoloquinolines allow functional group diversification on the quinoline nucleus, which proves to be highly advantageous for structural and biological activity assessments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclization
  • Iodine / chemistry*
  • Molecular Structure
  • Quinolines / chemical synthesis*
  • Quinolines / chemistry
  • Stereoisomerism

Substances

  • Quinolines
  • Iodine