Ethynyl, 2-Propynyl, and 3-Butynyl C-Phosphonate Analogues of Nucleoside Di- and Triphosphates: Synthesis and Reactivity in CuAAC

The synthesis and reactivity of a novel class of clickable nucleotide analogues containing a C-phosphonate subunit that has an alkyne group at the terminal position of the oligophosphate chain are reported. The C-phosphonate subunits were prepared by simple one- or two-step procedures using commercially available reagents. Nucleotides were prepared by MgCl2-catalyzed coupling reactions and then subjected to CuAAC reactions with various azide compounds to afford 5′-γ-labeled nucleoside triphosphates in excellent yields.