Asymmetric Synthesis of (R)‐β‐(Alkoxycarbonyl)aspartic Diesters (Derivatives of (R)‐Asa) with a Chiral Cationic Amino Acid Synthon

The scope of application of the bislactim ether method in the synthesis of amino acids has been broadened by the use of the chloride 1. Compound 1 serves as a cationic synthon, which reacts with nucleophiles. A prime example is the synthesis of 2, which can be hydrolyzed to give the title compounds 3.