Facile chemoselective synthesis of dehydroalanine-containing peptides

[GRAPHICS] Useful methodology is described for the synthesis of dehydroalanine residue s (II) within peptides. The unnatural amino acid (Se)-phenylselenocysteine (I) can be incorporated into growing peptide chains via standard peptide sy nthesis procedures. Subsequent oxidative elimination affords a dehydroalani ne at the desired position. The oxidation conditions are mild and tolerate functionalities commonly found in peptides, including variously protected c ysteine residues. To illustrate its utility, cyclic lanthionines have been synthesized by this method.