Synthesis of 2,6-disubstituted BODIPY dyes using palladium-catalyzed cross-coupling reaction with indium organometallics and indium-catalyzed alkyne hydroarylation reactions

During the last three decades the synthetic utility of indium(III) organometallics and halides have been continuously increased. Indium organometallics (R₃In) have been shown as useful reagents in metal-catalyzed cross-coupling reactions, and indium(III) halides have been shown as efficient π-acids for the electrophilic activation of alkynes towards nucleophilic additions. Furthermore, the application of these methodologies have allowed the synthesis of different natural products and novel organic materials. In this communication we report the synthesis of functionalized BODIPY dyes by palladium-catalyzed cross-coupling reaction with triorganioindum reagents and indium-catalyzed alkyne hydroarylation reactions.

BODIPY derivatives belong to a class of structurally fascinating compounds with interesting fluorescent properties with a wide range of applications.¹ Therefore, the development of new economical and sustainable strategies to functionalized BODIPYs with tunable spectral properties still of current interest. In this endeavor, the synthesis of 2,6-diaryl BODIPYs was achieved through two-fold Pd-catalyzed cross-coupling reaction of 2,6-dihalogenated BODIPys with triarylindium reagents. Likewise, we also found that indium(III)-catalyzed intermolecular double hydroarylation reactions of alkynes with meso-substituted BODIPYs provide a straightforward method for the synthesis of 2,6-dialkenylated BODIPYs in good yields with Markovnikov regioselectivity. Finally, the photophysical properties of the resulting BODIPYs were studied.

References

¹ A. Da Lama, J. Pérez Sestelo, L. A. Sarandeses, M. M. Martínez. J. Org. Chem. 2024, 89, 7402 and references therein.

Acknowledgments

We thank the Ministerio de Ciencia e Innovación−AgenciaEstatal de Investigación (Spain, PID2021-122335NB-I00) and Xunta de Galicia (GRC2022/039) for financial support. ADL thanks Xunta de Galicia for a predoctoral fellowship.