An innovative palladium-catalyzed alkenylation of peptides and vinyl iodides has been developed. This method does not require the introduction of a directing group and uses carboxylic acid groups as endogenous directing groups. It is noteworthy that two key building blocks for the ilamycins and CXCR7 modulators were prepared using our methodology. In addition, the free carboxylic acid residue can be linked to a variety of other compounds, providing a novel approach to the synthesis of peptide drugs in the future.