The Zn-proline complex is shown to catalyze the aldol reaction of acetone and a wide range of arenecarbaldehydes in aqueous media, accepting even deactivated arenecarbaldehydes such as methoxybenzaldehydes in good yields. Enantiomeric excesses of up to 56 % could be obtained with 5 mol-% of the catalyst at room temperature, and up to 66 %

Alcohols Q 0230A Selective Direct Aldol Reaction in Aqueous Media Catalyzed by Zinc-Proline.-The catalyst is shown to be effective for the reaction of a variety of aldehydes with ketones. Alcohol products are obtained with moderate to good enantioselectivity. The reaction of (XIII) with arenealdehydes affords mixtures of syn-and anti-products. The ratio (XIVa)/(XVa) is inverted using 50% of (XIIIa) additionally as co-solvent. -(FERNANDEZ-LOPEZ, R.; KOFOED, J.; MACHUQUEIRO, M.; DARBRE*, T.; Eur. J. Org. Chem. 2005, 24, 5268-5276; Inst. Chem. Biochem., Univ. Bern, CH-3012 Bern, Switz.; Eng.) -Y. Steudel 15-066