Metal-Free HB(C6F5)2-Catalyzed Hydrogenation of Unfunctionalized Olefins and Mechanism Study of Borane-Mediated σ-Bond Metathesis

摘要

Homogeneous hydrogenation of olefins is of great importance for both laboratory and industry synthesis. While most hydrogenation reactions are catalyzed by transition-metal complexes, the development of metal-free hydrogenation catalysts has recently attracted much attention because of their potential benefits of low cost and toxicity.Early efforts towards the metal-free catalytic hydrogenation of olefins or polyarenes employed boranes or diboranes, such as iBu3B, Et2BBEt2, or Pr2BBPr, as catalysts. These reactions require harsh reaction conditions (reaction temperature at 170-225 °C and H2 pressure at 100 bar), which often led to unwanted pyrolytic chain cleavage. The recent emerging chemistry of frustrated Lewis pairs provides a new strategy for metal-free hydrogenation which allows hydrogenation to be carried out under mild reaction conditions.