Tandem frustrated Lewis pair/tris(pentafluorophenyl)borane-catalyzed deoxygenative hydrosilylation of carbon dioxide

J Am Chem Soc. 2010 Aug 11;132(31):10660-1. doi: 10.1021/ja105320c.

Abstract

The frustrated Lewis pair system consisting of 2 equiv of 2,2,6,6-tetramethylpiperidine (TMP) and tris(pentafluorophenyl)borane [B(C(6)F(5))(3)] activates carbon dioxide to form a boratocarbamate-TMPH ion pair. In the presence of triethylsilane, this species is converted to a silyl carbamate and the known ion pair [TMPH](+)[HB(C(6)F(5))(3)](-), which recently was shown to react with CO(2) via transfer of the hydride from the hydridoborate to form the formatoborate [TMPH](+)[HC(O)OB(C(6)F(5))(3)](-). In the presence of extra B(C(6)F(5))(3) (0.1-1.0 equiv) and excess triethylsilane, the formatoborate is rapidly hydrosilated to form a formatosilane and regenerate [TMPH](+)[HB(C(6)F(5))(3)](-). The formatosilane in turn is rapidly hydrosilated by the B(C(6)F(5))(3)/Et(3)SiH system to CH(4), with (Et(3)Si)(2)O as the byproduct. At low [Et(3)SiH], intermediate CO(2) reduction products are observed; addition of more CO(2)/Et(3)SiH results in resumed hydrosilylation, indicating that this is a robust, living tandem catalytic system for the deoxygenative reduction of CO(2) to CH(4).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Boranes / chemistry*
  • Carbon Dioxide / chemistry*
  • Catalysis
  • Crystallography, X-Ray
  • Hydrocarbons, Fluorinated / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Oxygen / chemistry
  • Piperidines / chemistry*
  • Silanes / chemical synthesis*
  • Silanes / chemistry

Substances

  • 2,2,6,6-tetramethyl-1-piperidine
  • Boranes
  • Hydrocarbons, Fluorinated
  • Piperidines
  • Silanes
  • Carbon Dioxide
  • tris(pentafluorophenyl)borane
  • Oxygen