Asymmetric Synthesis of Arylpropionic Acids and Aryloxy Acids by Using Lactamides as Chiral Auxiliaries

Two different dynamic kinetic resolution methods have been applied for the asymmetric synthesis of pharmaceutical arylpropionic acids and aryloxy acids by using amides of (S)-lactic acid as chiral auxiliaries. For arylpropionic acids the esterification mediated by dicyclohexylcarbodiimide (DCC) and 4-(dimethylamino)pyridine (DMAP) proceeds with good asymmetric induction, while for aryloxyacetic acids the keystep is a diastereoselective substitution reaction in the presence of triethylamine and n-hexylammonium iodide as additives.