Asymmetric hydrogenation of ketones catalyzed by zeolite‐supported gelatin–Fe complex

Zeolite‐supported gelatin–iron complex (zeo–gelatin–Fe) was prepared from zeolite, gelatin and ferric chloride, and was found to be useful as a chiral catalyst for the asymmetric hydrogenation of some ketones to corresponding chiral alcohols, such as 2‐butanone to ( S )‐2‐butanol, acetophenone to ( R )‐1‐phenylethanol, diacetone alcohol to ( S )‐2‐methyl‐2,4‐pentane‐diol, 3‐methyl‐2‐butanone to ( R )‐3‐methyl‐2‐butanol and 4‐methyl‐2‐pentanone to ( R )‐4‐methyl‐2‐pentanol in 52–100% optical yields, respectively, at 20 ° C and under atmospheric hydrogen pressure. In the case of asymmetric hydrogenation of 3‐methyl‐2‐butanone to ( R )‐3‐methyl‐2‐butanol, when a proper content of iron in the zeo–gelatin–Fe complex and suitable reaction conditions were selected, the product and optical yields could be amounted to 80 and 100%, respectively, and the zeo–gelatin–Fe complex catalyst could be reused several times without remarkable change in the optical catalytic activity. Copyright © 2001 John Wiley & Sons, Ltd.