Dehydrooligopeptides. XVII. Practical Syntheses of All of the Diastereomers of N,N-Protected 2,3-Diaminobutanoic Acids from L- and D-Threonine Derivatives.

Syntheses of all of the diastereomers of 2,3-diaminobutanoic acids, found in some peptide antibiotics and toxins, were accomplished. The four isomers were derived mainly through two pathways including SN2 inversions of the β-substituent of L- or D-threonine derivatives. The various protecting groups and effective nucleophiles for the SN2 inversion were examined.