R. Moreira et al., New fluorogenic probes for oxygen and carbene transfer: A sensitive assay for single bead-supported catalysts, J AM CHEM S, 123(17), 2001, pp. 3927-3931
A high-throughput screening assay for atom transfer catalysis has been deve
loped. This assay is based on two probes, developed herein, which generate
highly fluorescent products upon carbene or oxygen atom transfer. The emiss
ion wavelength of probes 1 and 5 shift significantly (up to 90 nm) upon epo
xidation, allowing detection of product at 3% conversion. Probe 7 is not fl
uorescent, while fluorescence emission by carbene insertion/rearrangement p
roduct 8 allows detection at less than 1% conversion. Such sensitivity allo
ws for examination of single-bead reactions in a high throughput array form
at (1536 wells per plate), and provides a broad detection window ranging fr
om single to high turnover numbers. Thousands of metal complexes are evalua
ted in a single screening experiment. Preliminary screening of a diverse li
gand library with probe 7 in the presence of Rh(II) uncovered new catalysts
capable of cyclopropanation and C-H insertion.