Synthesis of non-symmetrical alkynylpyridines by chemoselective Sonogashira cross-coupling reactions

4-Bromo-2,3,5-trichloro-6-iodopyridine was studied as a new substrate in chemoselective Sonogashira reactions. This approach provides an efficient access to non-symmetrical mono-, di-, tri- and pentaalkynylated pyridines in good yields. Selected pentaalkynylated pyridines were studied with regard to their UV/Vis- and emission properties showing moderate to high fluorescence quantum yields. [Display omitted] •First Sonogashira reactions of 4-bromo-2,3,5-trichloro-6-iodopyridine.•Synthesis of novel non-symmetrical mono-, di-, tri- and pentaalkynylated pyridines in good yields.•Moderate to high fluorescence quantum yields.