Kinetic resolution of amino acids by phosphine oxide catalyzed enantioselective esterification

Chiral amino acids are essential building blocks in asymmetric synthesis and drug discovery, yet their efficient preparation from racemic mixtures remains challenging. Here we show that a rationally designed phosphine oxide catalyst derived from L-pyroglutaminol enables the highly efficient kinetic resolution of racemic amino acids under mild conditions. Using L-pyroglutaminol as the esterification reagent, this catalytic system delivers a broad range of chiral esters and recovered amino acids with excellent stereoselectivities (s > 1057). Mechanistic studies suggest that the superior stereocontrol arises from a cooperative double hydrogen-bonding interaction between the catalyst and the pyroglutaminol core. This work provides a practical and scalable approach to enantioenriched amino acids, highlighting the potential of dual chiral cooperative catalysis in asymmetric synthesis.