Fluorogenic Transformations Based on Formation of CC Bonds Catalyzed by Palladium: An Efficient Approach for High Throughput Optimizations and Kinetic Studies

Abstract

Abstract:We have developed novel fluorogenic transformations based on formation of C À C bonds catalyzed by palladium using iodocoumarin 1 as a model aryl iodide, where fluorescence is quenched completely due to effects of the heavy, polarizable iodine atom. Substitution of the iodine atom for the carbon using Sonogashira, Suzuki-Miyaura and Heck couplings results in a dramatic fluorescence enhancement. This approach has been used successfully for the optimization of reaction conditions and kinetic studies in high throughput format.

Fluorophore tagged cross-coupling catalysts

“…Fluorescencebased approaches have been used in cross-coupling reactions, but this has been limited mainly to examine product formation with fluorophores attached to coupling partners. [2][3][4][5] Tagging with a fluorescent dye enables the detection of Pd complexes down to the single molecule limit as demonstrated recently by Blum et al with fluorescence microscopy. 6 Herten et al have shown that the formation and dissociation of individual ligands from metal complexes can be monitored by singlemolecule fluorescence spectroscopy.…”

Optical monitoring of polymerizations in droplets with high temporal dynamic range

“…Fluorogenic transformations rely on practically non-uorescent reactants which yield strongly uorescent products upon reaction, and have been used to monitor a variety of chemical transformations. 24,26,[54][55][56][57][58][59][60] Closely related to uorogenic reactions, spectral shis as a result of a change in functionality or extension of conjugation length have also been used to monitor chemical reactions. 61,62 These methods generally require the use of reagents that have been specically engineered to provide the measured response.…”

Development of a Fluorogenic Reactivity Palette for the Study of Nucleophilic Addition Reactions Based on meso-Formyl BODIPY Dyes

“…A significant effort has been devoted over the past decade toward developing fluorogenic probes for reaction screening. − A number of fluorescence-based assays have been reported to monitor and study bond formation in a diverse set of reactions including aldol reactions, − Mannich-type reactions, Michael additions, − and palladium-catalyzed reactions. − These assays, using fluorescence intensity as a marker, provide a rapid, in situ screening platform that is of simple application and requires minimum equipment investment.…”