Development of Tartaric Acid Derived Chiral Guanidines and Their Application to Catalytic Enantioselective α-Hydroxylation of β-Dicarbonyl Compounds

A novel library of chiral guanidines featuring a tartaric acid skeleton was developed from diethyl L-tartrate. These guanidines are easily accessed with tunable style and electronic properties. The utilities of the guanidines were highlighted by their ability to catalyze the alpha-hydroxylation of beta-ketoesters and beta-diketones with remarkable efficiency and excellent enantioselectivity.