Dehydropeptides from orthogonal ligation of unprotected peptides.

A facile method has been developed to synthesize linear and cyclic dehydropeptides from unprotected peptide precursors. This method exploits an N-terminal Cys for a Cys-thioester ligation to generate an unprotected peptide and as a precursor for conversion to DeltaAla by beta-elimination under mild conditions.