L-t-Leucine-catalyzeddirectasymmetricaldolreactions are described. In the aldolreaction of p-nitrobenzaldehyde with a cyclicketone at room temperature, L-t-leucine exhibits catalytic activity resulting in moderate to high diastereo- and enantioselectivity. Use of cycloheptanone or cyclooctanone as a substrate resulted in production of the syn selective product.