Pd-catalyzed synthesis of C-C (Sonogashira, Suzuki Heck, Stille), C-P and C-S linked products using gem-dibromovinyl BODIPY

The chemistry of gem-dibromovinyl derivatives has undergone a renaissance through the application of palladium catalysis and has been applied to pyrrole substituted gem-dihromovinyl BODIPY. gem-Dibromovinyl BODIPYs (substituted at either the p-position of 8-phenyl or the beta-position of the pyrrole rings) were studied for cross-coupling reactions using Sonogashira, Suzuki, Heck and Stille conditions, and with phosphonates and thiols. The assigned structures were supported by MS and H-1 NMR, C-13 NMR , X-ray diffraction analysis as well as optical spectroscopy. The conjugates were investigated for their absorption, fluorescence and solvatochromic properties in different solvents. Substitution at the p-position of 8-phenyl derivatives of gem-diethynyl BODIPYs did not induce any shift in the absorption maximum, while the beta-position pyrrole substituted derivatives showed a red shift. Aromatic compounds gave larger red shifts as compared to the aliphatic substituted analogs.