Regioselective and Stepwise Syntheses of Functionalized BODIPY Dyes through Palladium-Catalyzed Cross-Coupling Reactions and Direct C–H Arylations

Regioselective and
stepwise syntheses of a series of functionalized
BODIPY dyes through palladium-catalyzed cross-coupling reactions and
direct C–H arylations have been developed. In particular, this
method allows the straightforward synthesis of 2,6-dibromo-3,5-diarylBODIPYs
and 2-bromo-3-arylBODIPYs from polybrominated BODIPYs. The X-ray structure
of intermediates 5a–c indicated that
the palladium was first inserted into the C–Br bonds at 3,5-positions
of brominated BODIPYs. The resulting 2,6-dibromo-substituted BODIPYs
are potential long wavelength photosensitizers which are not easily
accessible using previous methods.