A solution-phase assay based on fluorescence resonance energy transfer (FRET) was developed for high-throughput screening of palladium catalyzed aminations of aryl halides. Dansylpiperazine was used as the fluorescent component and a chloro-or bromoarene tagged with an azodye as the quenching partner. Fluorescence intensities of reaction aliquots correlated linearly with reaction yield after dilution to appropriate concentrations. ...