Kinetic Resolution of α-Methylene-β-hydroxy Esters Catalyzed by Acyl Transfer CatalystAn-PIQ

A highly efficient nonenzymatic kinetic resolution of a series of structurally diverse racemic α-methylene-β-hydroxy esters utilizing the acyl transfer catalyst An-PIQ and propionic anhydride is reported. This procedure provides recovered alcohols with extremely high ee's (up to >99%) in reasonable conversions and excellent selectivity factors (S up to 108). Several synthetically important substrates were resolved in gram-scale reactions, and highly optically pure α-methylene-β-hydroxy esters were obtained with excellent S values and good yields.