Stereoselective Synthesis of 1-Amino-2-azidocyclopropanecarboxylic Acid Derivatives

2-Azidocyclopropane-1,1-dicarboxylic esters were transformed into orthogonally N-protected alkyl 1-amino-2-azidocyclopropanecarboxylates via stereoselective monosaponification and subsequent Curtius reaction. Following deprotection of the ester function or the Boc-protected amino group, the first derivatives of a novel class of conformationally constrained cyclopropane α,β-diamino carboxylic acids were made accessible.