Catalytic, asymmetric synthesis of cyanohydrin esters: The effect of anhydride structure on enantioselectivity

A bimetallic titanium(salen) complex has been shown to catalyse the asymmetric addition of potassium cyanide to aldehydes in the presence of a range of anhydrides. leading to cyanohydrin esters. Linear aliphatic anhydrides (acetic and propionic) gave products with higher enantiomeric purity than those obtained using pivalic or benzoic anhydrides.