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 steric and electronic properties. The utilities of the guanidines were highlighted by their ability to catalyze the α-hydroxylation of β-ketoesters and β-diketones with remarkable efficiency and excellent enantioselectivity.