A method of controlling the diastereoselectivity of the nitroaldol reaction by the use of titanium, zirconium and aluminum based Lewis acids is disclosed. In a preferred embodiment, the reaction of lithium nitronate anion with aldehydes in THF/CH.sub.2 Cl.sub.2 at reduced temperature in the presence of isopropoxy titanium trichloride (TiCl.sub.3 (OPr.sup.i)) yields nitro alcohols enriched in the erythro diastereomer. Erythro-threo ratios of 11.2:1-3.4:1 for aromatic aldehydes and 3.8:1-1:1 for aliphatic aldehydes are typically obtained.