Synthesis of L-Azetidine-2-Carboxylic Acid

L-Azetidine-2-carboxylic acid, the first known example naturally occurring azetidine, was synthesized in a novel, simple, clean and improved procedure. It was synthesized from γ-butyrolactone through four steps: bromination and esterification, cyclization, hydrogenation and resolution. The overall yield could reach 13.2%.