Total Synthesis and Biological Investigation of (−)-PromysalinAndrew D. Steele, Kyle W. Knouse, Colleen E. Keohane, and William M. Wuest*Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States* S Supporting InformationABSTRACT: Compounds that specifically target patho-genic bacteria are greatly needed, and identifying themethod by which they act would provide new avenues oftreatment. Herein we report the concise, high-yieldingtotal synthesis (eight steps, 35% yield) of promysalin, anatural product that displays antivirulence phenotypesagainst pathogenic bacteria. Guided by bioinformatics, fourdiastereomers were synthesized, and the relative andabsolute stereochemistries were confirmed by spectral andbiological analysis. Finally, we show for the first time thatpromysalin displays two antivirulence phenotypes: thedispersion of mature biofilms and the inhibition ofpyoverdine production, hinting at a unique pathogenic-specific mechanism of action.