Unprecedented α-substituted BOPHY dyes via a key 3,8-dichloroBOPHY intermediate

- High yielding synthesis towards 3,8-dichloroBOPHY.
- 3,8-dichloroBOPHY as a key intermediate towards red-shifted fluorophores.
- Nucleophilic substitution and palladium-catalyzed reactions on 3,8-dichloroBOPHY.

We present a high-yielding synthesis for 3,8-dichloroBOPHY. Starting from unsubstituted pyrrole, this α-halogenated fluorophore was obtained in 51% yield. Subsequent functionalization via nucleophilic substitutions with O, N and S-nucleophiles was achieved in yields up to 88%. Stille and Sonogashira coupling reactions led to red-shifted chromophores. The absorption maxima of the synthesized dyes vary from 442 to 545 nm, with emission maxima ranging from 474 to 612 nm and quantum yields of fluorescence in solution from <1% to 100%.

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