The synthesis of constrained x, B- or x, Y-diamino acid derivatives as building blocks for new substituted 2,4-diaminobutyric acid derivatives is of great importance in medicinal and agricultural chemistry. This research concerns the development of stereoselective syntheses and biochemical evaluation of new derivatives of 1,2-diaminocyclopropane-1-carboxylic acid, 2-amino-2-aziridin-2-ylacetic acid and 2-amino-3-aziridin-2-ylpropionic acid and also the study of their ring opening reactions towards potentially physiologically active amino acid derivatives.