7-Deaza-7-Iodo-2',3'-dideoxyadenosine (also named as 7-I-7-Deaza-ddA) is typically used as a reagent in the gene sequencing and mapping.

 Palladium-Catalyzed Synthesis of Alkynylamino Nucleosides. A Universal Linker for Nucleic Acid. [1]

 Solvent, not palladium oxidation state, is the primary determinant for successful coupling of terminal alkynes with iodo-nucleosides. [2]

 References:

[1] F.W.Hobbs, J. Org. Chem., 1989, 54(14), pp 3420-3422.

[2] M.J.Robins, et al, Tetrahedron Lett., 1990, 31(26), pp 3731-3734.