Research On AuNPore Catalyst For Selective Hydrogenation Of Cinnamaldehydes

As one of the important organic intermediates, cinnamyl alcohol is used in the synthesis of fine chemicals, such as flavor, perfume, pharmaceutical compounds and functional materials. Thermodynamically and kinetically, hydrogenation of cinnamaldehyde to cinnamyl alcohol is a difficult reaction, because a C=C bond is more easily hydrogenated than a C=O bond. Thus, selective hydrogenation of cinnamaldehyde to cinnamyl alcohol is still a challenging work.In this paper, a further exploration and research on the selective hydrogenation of cinnamaldehydes to cinnamyl alcohols was used the novel and green unsupported nanoporous gold (AuNPore) as a catalyst and organosilanes with water as a hydrogen source, and the selective hydrogenation of cinnamaldehydes has been successfully obtained in an mild condition.1. Hydrogenation of cinnamaldehyde was selected as the model reaction, we examined the effect of hydrogen sources, bases and solvents on the reaction and optimized the condition: using2mol%AuNPore as the catalyst,3equivalent triethylsilane with6equivalent water as the hydrogen source, acetonitrile as the solvent,20mol%Et3N as the additive, selective hydrogenation of cinnamaldehyde occurred at70℃for24h to afford cinnamyl alcohol in73%yield. Under the optimized condition described above, different substituted cinnamaldehydes had been performed smoothly, and the yields of substituted cinnamyl alcohols were within42-79%.2. It was found that the reaction had highly selectivity and better reproducibility. Moreover, the AuNPore catalyst was easily recoverable and could be reused three times without any loss of catalytic activity. This reaction offered a new approach for preparation of cinnamyl alcohol and had important theoretical significance.