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 Diels-Alder reaction (endo:exo > 1:25) is the key step. Azido coronatine was as effective as the original coronatine in a stomatal opening assay, and was easily modified to a fluorescein isothiocyanate (FITC)-labeled probe with high yield.