Preparation of silica-supported alginic acid-L-glutamic acid-Pt complex and its catalytic behaviors in asymmetric hydrogenation of 4-methyl-2-pentanone

A new chiral polymer-metal complex, silica-supported alginic acid-L-glutamic acid-Pt complex (SiO2-AA-L-Glu-Pt), has been prepared by a very simple method and has been found to be able to catalyze the asymmetric hydrogenation of 4-methyl-2-pentanone to give (R)-(-)-4-methyl-2-pentanol in 90.8% optical yield at 30degreesC and under 1 atm H-2. The product and optical yields were greatly affected by the Pt content in the complex, the solvent, the 4-methyl-2-pentanone/Pt molar ratio and the reaction temperature. The catalyst could be reused several times without any great change in its optical catalytic activity. Copyright (C) 2003 John Wiley Sons, Ltd.