[reaction: see text]1,2-Dithiolanes present several points of interest for both peptide and medicinal chemistry, yet no chiral alpha-amino acids containing this five-membered heterocyclic system are available. We report here the first synthesis of N- and C-protected derivative of (S)-2-amino-3-(1,2-dithiolan-4-yl)propionic acid (Adp) and its 1,3-dithiolic form.