Enantioselective Nitroaldol Reaction of α-Keto-esters Catalyzed by Cinchona Alkaloids

Significance The authors report an enantioselective organocatalytic nitroaldol reaction of α-ketoesters. Bifunctional monomeric C6′-OH cinchona alkaloids were found to be effective catalysts for the 1,2-additions to carbonyls. With 5 mol% of catalyst 1 high yields (86-98%) and excellent enantioselectivities (93-97%) are obtained for a wide range of α-ketoesters. High chemoselectivities (>95:5) have also been attained for the challenging alkenyl α-ketoesters.