Asymmetric hydrogenation of ethyl pyruvate on chirally modified Pt catalysts supported on periodic mesoporous resols

5.0% (Mass fraction) Pt catalysts supported on FDU-14, a kind of periodic mesoporous resols, were prepared by an impregnation method using two different Pt precursors, H₂PtCl₆ and Pt (NH₃)₄Cl₂. These Pt/FDU-14 catalysts were characterized by XRD, N₂-sorption, TEM and CO chemisorption. The Pt/FDU-14 catalysts can be effectively applied in the asymmetric hydrogenation of ethyl pyruvate after chirally modified with cinchonidine. The Pt/FDU-14 catalysts derived from H₂PtCl₆ afforded better conversions of ethyl pyruvate due to higher Pt dispersion and smaller Pt particle size, the initial activity (TOF) reaching 21092 mol/(mol·h) in acetic acid. While the Pt/FDU-14 catalysts derived from Pt (NH₃)₄Cl₂ exhibited higher chiral induction ability and as high as 81.4% e.e. value of (R)-(+)-ethyl lactate was achieved in acetic acid. Due to the strong hydrophobicity of FDU-14 with pure organic framework, Pt/FDU-14 also worked well in water and can be recycled easily for more than 10 times without distinct loss of activity or enantioselectivity.