Stereoselective synthesis of ( R )- and ( S )-1,2-diazetidine-3-carboxylic acid derivatives for peptidomimetics.

The stereoselective synthesis of both enantiomers of N -protected 1,2-diazetidine-3-carboxylic acid (aAze) from homochiral glycidol is described. Orthogonal protection of this novel cyclic α-hydrazino acid allows for selective functionalisation at either N γ or N δ . This novel peptidomimetic building block was incorporated into the pseudotripeptides Gly-γaAze-Ala and Gly-δaAze-Ala.