Nano SiO2-bonded Ru-TsDPEN for catalytic resolution of 1,2-propanediol by two transfer hydrogenation

A new strategy was introduced for the catalytic resolution of 1,2-propanediol involving the successive oxidative kinetic resolution and asymmetric hydrogenation by two hydrogen transfer reactions catalyzed by nano SiO 2 -bonded Ru-TsDPEN [TsDPEN = N -( p -toluenesulfonyl)-1,2-diphenylethylene diamine]-derived catalysts composed of two opposite configurations. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry-derivative thermogravimetry (TG-DTG) analysis, and inductively coupled plasma atomic emission spectrometry (ICP-AES). Results showed that Ru-TsDPEN derived catalysts were successfully grafted on the nano SiO 2 , affording high catalytic conversions of >99 and 99%, selectivities of 47 and 98% and maximum ee values of >99 and >99% in the two reactions, which were due to the nano SiO 2 with Ru-TsDPEN in the reaction system with high dispersion. Additionally, the catalysts exhibited excellent durability and were filtered and reused at least five times without noticeable catalysts deactivations.