Synthesis of Carboxylic Acids from Saccharides, CO₂, and H₂

Here we report a strategy to synthesize C-7 carboxylicacids via the reaction of glucose, CO2 and H-2. The reaction can be realized using Rh-(acac)-(CO)(2) ascatalyst and I-2 as promoter in the binary solvent of aceticacid and water at 160 degrees C. The strategy also applies to otherC(n) saccharides, where the corresponding Cn+1 carboxylic acids could be obtained and the yield of the acids canreach 72% when glyceraldehyde was used. The reaction pathway was proposedbased on a series of control experiments. This work utilized saccharideand CO2 simultaneously via C-C bond formation, whichopens a promising way of biomass utilization and CO2 conversion.