Oligonucleotides with 5-ethynyl residues may be used in transition metal-catalyzed coupling reactions. Two ethynyl-bearing oligonucleotides can be homo-coupled via a diyne linkage using copper catalysis. Further, the ethynyl groups may be used in copper-catalyzed couplings with arylacetylenes bearing anthraquinone, biotin, or fluorescein appendages.⁽¹⁾ Palladium catalyzed cross-coupling of ethynyl-dU-bearing oligonucleotidies with 2-iodoanthraquinone provides anthraquinone-bearing nucleic acids useful in electrochemical applications of DNA.⁽²⁾

Ref:

1. Minakawa, N.; Ono, Y.; Matsuda, A. J. Am. Chem. Soc. 2003, 125, 11545-11552.
2. Gorodetsky, A. A.; Green, O.; Yavin, E.; Barton, J. K. Bioconjugate Chem. 2007, 18, 1434-1441.