Direct arylation of electron-poor indolizines

Derivatized indolizines efficiently prepared via direct arylation, exhibit violet, blue or green fluorescence depending on the nature of substituents. By attaching two electron-withdrawing groups to five-membered ring it is possible to access a range of multi-substituted stable indolizine-based fluorophores. Compounds featuring this scaffold display advantageous combination of optical properties including reasonable fluorescence quantum yield combined with large Stokes shifts.