Synthesis Of Polymer-Supported Ru Catalysts And Application In The Asymmetric Transfer Hydrogenation Of Acetophonone

In this article, the organosoluble polystyrene polymer containing phosphonate group had been synthesized by using 1R,2R-Diaminocyclohexane as raw material through several steps (p-toluenesulfonyl and radical polymerization reaction). Upon the immobilization of [RuCl2(p-cymene)]2 on the synthesized polystyrene polymer by the complexation reaction of amino group with metal ruthenium, catalysts 4a-c organosoluble in THF, DMF, DMSO, CH2Cl2, CHCl3, CH3CN, CH3OH and so on in acidic medium were prepared. After the catalytic reaction was completed, ethyl acetate was added, and then supported ruthenium catalyst 4c precipitated out and recycled in 87-93% yield.The structure and surface morphology had been characteried by IR, TG, XPRD, SEM, TEM, and N2 adsorption-desorption isotherm. It was shown that 3c is a novel type of catalyst support possessed the filiform and microporous structure with 20-50 nm width and 1-20A micropores.In the asymmetric transfer hydrogenation of acetophenone and it derivatives, the optinum catalytic conditions such as the supported amount of transitional metal ruthenium, solvent, temperature and reaction time were screened in details. The products of acetophenone and it derivatives in 41.3-99% conversion and 80.1-97.3% ee without side-products (100% chemical selectivity) were obtained at 50℃for 6 h in methanol containing 1.72 mol/mL substrates by using 10 wt% Ru catalyst (S/C=100).