Azido-Coronatine: A Useful Platform for Click Chemistry-Mediated Probe Synthesis for Bioorganic Studies

We report on the development of azide-coronatine as a useful platform for azide alkyne cycloaddition (click chemistry)-mediated synthesis of molecular probes. (+)-Azido-coronatine was synthesized in 10 steps with 11% yield using improved synthesis of coronafacic acid, in which the highly exo-selective Die Is-Alder reaction (endo:exo > 1:25) is the key step. Azido coronatine was as effective as the original coronatine in a stomata! opening assay, and was easily modified to a fluorescein isothiocyanate (FITC)-labeled probe with high yield.