An efficient synthesis of a probe for protein function: 2,3-diaminopropionic acid with orthogonal protecting groups.

[reaction: see text] An efficient and cost-effective synthesis of N(alpha)-Boc2-N(beta)-Cbz-2,3-diaminopropionic acid is reported. The synthesis starts from commercially available N(alpha)-Boc-Asp(OBn)-OH and employs a Curtius rearrangement to establish the beta-nitrogen. Proper protection of the alpha-nitrogen is essential for the success of the Curtius rearrangement.