Jilei Xu

Herein, a new route was presented to synthesize 2-benzimidazolones via the carbonylation of o-phenylenediamines with CO2 catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-based ionic liquids under solvent-free conditions. DBU acetate ([DBUH][OAc]) displayed high efficiency for catalyzing the reactions of CO2 with o-phenylenediamines, and a series of benzimidazolones were obtained in high yields. It was demonstrated that [DBUH][OAc] could serve as a bifunctional catalyst for these reactions with the cation activating CO2 and the anion activating o-phenylenediamines. This protocol provides an effective and environmentally friendly alternative route for production of benzimidazolones, and extends the chemical utilization of CO2 in organic synthesis as well.

The selective oxidation of glycerol was investigated using AuPd/TiO2 as the catalyst in the presence of AlCl3, and lactic acid was obtained as the predominant product. It was demonstrated that AuPd/TiO2 and AlCl3 played synergistic roles in the production of lactic acid. The possible reaction pathway was proposed, in which glycerol was first oxidized to glyceraldehyde and dihydroxyacetone, catalysed by AuPd/TiO2, followed by the formation of lactic acid, catalyzed by AlCl3.

The cyclization of o-phenylenediamines by CO2 in the presence of H2 was presented to directly synthesize benzimidazoles, and a series of benzimidazoles were obtained in excellent yields using RuCl2(dppe)2 as the catalyst.

Pd/C-catalyzed direct formylation of aromatic iodides to aryl aldehydes using CO2 as a C1 resource was realized for the first time in the presence of hydrosilanes and base DBU under mild conditions, giving a series of aldehydes in good yields.