A simple iridicycle catalyst for efficient transfer hydrogenation of N-heterocycles in water

Chemistry. 2015 Mar 27;21(14):5370-9. doi: 10.1002/chem.201500016. Epub 2015 Feb 26.

Abstract

A cyclometalated iridium complex is shown to catalyse the transfer hydrogenation of various nitrogen heterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional-group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinoline reduction suggests that the transfer hydrogenation proceeds via both 1,2- and 1,4-addition pathways, with the catalytic turnover being limited by the step of hydride transfer.

Keywords: N-heterocycles; green chemistry; iridium; transfer hydrogenation; water.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Coordination Complexes / chemistry
  • Heterocyclic Compounds / chemistry*
  • Hydrogenation
  • Iridium / chemistry*
  • Water / chemistry*

Substances

  • Coordination Complexes
  • Heterocyclic Compounds
  • Water
  • Iridium