Kinetic Resolution of Racemic Mandelic Acid Esters by N, N′-Dioxide-Scandium-Complex-Catalyzed Enantiomer-Selective Acylation

A simple and efficient acylative kinetic resolution of racemic mandelic acid esters was accomplished with a chiral N, N'-dioxide-scandium(III) complex under mild and base-free reaction conditions. A variety of mandelic acid esters performed well in the reaction, obtaining both acylat-ed products (up to 49% yield, 97% ee) and recovered substrates (up to 49% yield, 95% ee) in high enantioselectivities with perfect selectivity factors (up to 247). The enantioselective recognition and catalytic models were also proposed for the catalytic KR reaction.