We have previously reported a study of the synthesis of amino acids using Diels–Alder (D–A) adducts of dienes and N-containing dienophiles.1,2) Subsequently, our interests turned to the synthesis of additional amino acids from other N-containing olefins, which can be prepared by pericyclic re- action. In the present paper, we would like to report the synthesis of azetidine-cis-2,3-dicarboxylic acid (1) using the electro- cyclic reaction of 1,2- ...