Total synthesis of a peptide diatom sex pheromone bearing an unusual sulfated aspartic acid

The peptide Sex Inducing Pheromone SIP+ bearing an unusual sulfated aspartic acid residue induces sexual reproduction in diatom populations. Herein, we report the first total synthesis of SIP+ using both a sulfated building block approach and a SPPS compatible late-stage sulfation strategy to assemble the natural product. The modular approaches provide concise routes to useful quantities of the natural product for future SAR investigations examining the role of SIP+ in diatom biology.