A highly active phosphine-borane organocatalyst for the reduction of CO2 to methanol using hydroboranes

J Am Chem Soc. 2013 Jun 26;135(25):9326-9. doi: 10.1021/ja404585p. Epub 2013 Jun 14.

Abstract

In this work, we report that organocatalyst 1-Bcat-2-PPh2-C6H4 ((1); cat = catechol) acts as an ambiphilic metal-free system for the reduction of carbon dioxide in presence of hydroboranes (HBR2 = HBcat (catecholborane), HBpin (pinacolborane), 9-BBN (9-borabicyclo[3.3.1]nonane), BH3·SMe2 and BH3·THF) to generate CH3OBR2 or (CH3OBO)3, products that can be readily hydrolyzed to methanol. The yields can be as high as 99% with exclusive formation of CH3OBR2 or (CH3OBO)3 with TON (turnover numbers) and TOF (turnover frequencies) reaching >2950 and 853 h(-1), respectively. Furthermore, the catalyst exhibits "living" behavior: once the first loading is consumed, it resumes its activity on adding another loading of reagents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Boranes / chemistry*
  • Carbon Dioxide / chemistry*
  • Catalysis
  • Methanol / chemical synthesis*
  • Methanol / chemistry
  • Molecular Structure
  • Oxidation-Reduction
  • Phosphines / chemistry*

Substances

  • Boranes
  • Phosphines
  • Carbon Dioxide
  • phosphine
  • Methanol